CONTRIBUTING.md - fix links

Author: mrogowski

CONTRIBUTING.md

@@ -13,9 +13,9 @@ Thanks for taking the time to contribute!
 
 > If you want to ask a question, we assume you have read the available [documentation](https://shmem4py.readthedocs.io/).
 
-Before you ask a question, it is best to search for existing [Issues](/issues) that might help you. In case you have found a suitable issue and still need clarification, you can write your question in this issue. It is also advisable to search the internet for answers first. Please note that many questions regarding the programming model itself and suggestions for its enhancements may better belong to the [OpenSHMEM Community](http://openshmem.org/site/Community) rather than the shmem4py project, which is naturally constrained by the specification and underlying OpenSHMEM implementations.
+Before you ask a question, it is best to search for existing [Issues](https://github.com/mpi4py/shmem4py/issues) that might help you. In case you have found a suitable issue and still need clarification, you can write your question in this issue. It is also advisable to search the internet for answers first. Please note that many questions regarding the programming model itself and suggestions for its enhancements may better belong to the [OpenSHMEM Community](http://openshmem.org/site/Community) rather than the shmem4py project, which is naturally constrained by the specification and underlying OpenSHMEM implementations.
 
-If you still feel the need to ask a question or clarification, we recommend opening a [Discussion (Q&A)](/discussions/new?category=q-a). Please remember to provide as much context as possible about what you're running into and report project and platform versions depending on what seems relevant.
+If you still feel the need to ask a question or clarification, we recommend opening a [Discussion (Q&A)](https://github.com/mpi4py/shmem4py/discussions/new?category=q-a). Please remember to provide as much context as possible about what you're running into and report project and platform versions depending on what seems relevant.
 
 We will then take care of the issue as soon as possible.
 
@@ -32,7 +32,7 @@ A good bug report shouldn't leave others needing to chase you for more informati
 
 - Make sure that you are using the latest version.
 - Determine if your bug is really a bug and not an error on your side, e.g., using incompatible environment components/versions (Make sure that you have read the [documentation](https://shmem4py.readthedocs.io/).
-- To see if other users have experienced (and potentially already solved) the same issue you are having, check if there is not already a bug report existing for your bug or error in the [bug tracker](issues?q=label%3Abug).
+- To see if other users have experienced (and potentially already solved) the same issue you are having, check if there is not already a bug report existing for your bug or error in the [bug tracker](https://github.com/mpi4py/shmem4py/issues).
 - Also, make sure to search the internet (including Stack Overflow) to see if users outside of the GitHub community have discussed the issue.
 - Collect information about the bug:
   - Stack trace (Traceback)
@@ -46,7 +46,7 @@ A good bug report shouldn't leave others needing to chase you for more informati
 
 We use GitHub issues to track bugs and errors. If you run into an issue with the project:
 
-- Open an [Issue](/issues/new).
+- Open an [Issue](https://github.com/mpi4py/shmem4py/issues/new).
 - Explain the behavior you would expect and the actual behavior.
 - Please provide as much context as possible and describe the *reproduction steps* that someone else can follow to recreate the issue on their own. This usually includes your code. For good bug reports, you should isolate the problem and create a reduced test case.
 - Provide the information you collected in the previous section.
@@ -60,14 +60,14 @@ This section guides you through submitting an enhancement suggestion for shmem4p
 
 - Make sure that you are using the latest version.
 - Read the [documentation](https://shmem4py.readthedocs.io/) carefully and find out if the functionality is already covered, maybe by an individual configuration.
-- Perform a [search](/issues) to see if the enhancement has already been suggested. If it has, add a comment to the existing issue instead of opening a new one.
+- Perform a [search](https://github.com/mpi4py/shmem4py/issues) to see if the enhancement has already been suggested. If it has, add a comment to the existing issue instead of opening a new one.
 - Find out whether your idea fits with the scope and aims of the project. It's up to you to make a strong case to convince the project's developers of the merits of this feature. Keep in mind that we want features that will be useful to the majority of our users and not just a small subset. If you're just targeting a minority of users, consider writing an add-on/plugin library.
 - Consider whether your suggestion applies to shmem4py or [OpenSHMEM](http://openshmem.org/).
 
 
 #### How Do I Submit a Good Enhancement Suggestion?
 
-Enhancement suggestions are tracked as [GitHub issues](/issues).
+Enhancement suggestions are tracked as [GitHub issues](https://github.com/mpi4py/shmem4py/issues).
 
 - Use a **clear and descriptive title** for the issue to identify the suggestion.
 - Provide a **step-by-step description of the suggested enhancement** in as many details as possible.