Change 'master' branch to 'main'

Author: sethmlarson

.ci/jobs/defaults.yml

@@ -15,7 +15,7 @@
     parameters:
     - string:
         name: branch_specifier
-        default: refs/heads/master
+        default: refs/heads/main
         description: the Git branch specifier to build (<branchName>, <tagName>,
           <commitId>, etc.)
     properties:

.ci/jobs/elastic+elasticsearch-rs+master.yml renamed to .ci/jobs/elastic+elasticsearch-rs+main.yml

@@ -1,13 +1,13 @@
 ---
 - job:
-    name: elastic+elasticsearch-rs+master
-    display-name: 'elastic / elasticsearch-rs # master'
-    description: Testing the elasticsearch-rs master branch.
+    name: elastic+elasticsearch-rs+main
+    display-name: 'elastic / elasticsearch-rs # main'
+    description: Testing the elasticsearch-rs main branch.
     junit_results: "*-junit.xml"
     parameters:
       - string:
           name: branch_specifier
-          default: refs/heads/master
+          default: refs/heads/main
           description: The Git branch specifier to build
     triggers:
       - github

CONTRIBUTING.md

@@ -96,7 +96,7 @@ The workspace contains the following packages:
 
   The client package crate. The client exposes all Elasticsearch APIs as associated functions, either on
 the root client, `Elasticsearch`, or on one of the _namespaced clients_, such as `Cat`, `Indices`, etc. The _namespaced clients_
-are based on the grouping of APIs within the [Elasticsearch](https://github.com/elastic/elasticsearch/tree/master/rest-api-spec) and [X-Pack](https://github.com/elastic/elasticsearch/tree/master/x-pack/plugin/src/test/resources/rest-api-spec/api) REST API specs from which much of the client is generated.
+are based on the grouping of APIs within the [Elasticsearch](https://github.com/elastic/elasticsearch/tree/main/rest-api-spec) and [X-Pack](https://github.com/elastic/elasticsearch/tree/main/x-pack/plugin/src/test/resources/rest-api-spec/api) REST API specs from which much of the client is generated.
 All API functions are `async` only, and can be `await`ed.
 
 - #### `api_generator`

README.md

@@ -34,7 +34,7 @@ The following are a list of Cargo features that can be enabled or disabled:
 
 The client exposes all Elasticsearch APIs as associated functions, either on
 the root client, `Elasticsearch`, or on one of the _namespaced clients_, such as `Cat`, `Indices`, etc. The _namespaced clients_
-are based on the grouping of APIs within the [Elasticsearch](https://github.com/elastic/elasticsearch/tree/master/rest-api-spec) and [X-Pack](https://github.com/elastic/elasticsearch/tree/master/x-pack/plugin/src/test/resources/rest-api-spec/api) REST API specs from which much of the client is generated.
+are based on the grouping of APIs within the [Elasticsearch](https://github.com/elastic/elasticsearch/tree/main/rest-api-spec) and [X-Pack](https://github.com/elastic/elasticsearch/tree/main/x-pack/plugin/src/test/resources/rest-api-spec/api) REST API specs from which much of the client is generated.
 All API functions are `async` only, and can be `await`ed.
 
 ### Installing