chore: migrate to main as default branch (#7792)

We make `main` the default branch.

Contributors should update their local clone:

```
git remote set-head origin -a
```

## Checklist

- [x] Change(s) are motivated and described in the PR description.
- [x] Testing strategy is described if automated tests are not included
in the PR.
- [x] Risk is outlined (performance impact, potential for breakage,
maintainability, etc).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] [Library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
are followed. If no release note is required, add label
`changelog/no-changelog`.
- [x] Documentation is included (in-code, generated user docs, [public
corp docs](https://github.com/DataDog/documentation/)).
- [x] Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist

- [x] Title is accurate.
- [x] No unnecessary changes are introduced.
- [x] Description motivates each change.
- [x] Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes unless absolutely necessary.
- [x] Testing strategy adequately addresses listed risk(s).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] Release note makes sense to a user of the library.
- [x] Reviewer has explicitly acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment.
- [x] Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)
- [x] If this PR touches code that signs or publishes builds or
packages, or handles credentials of any kind, I've requested a review
from `@DataDog/security-design-and-guidance`.
- [x] This PR doesn't touch any of that.

Author: majorgreys

.github/workflows/system-tests.yml

@@ -3,7 +3,7 @@ name: System Tests
 on:
   push:
     branches:
-      - 2.x
+      - main
   pull_request:
   workflow_dispatch: {}
   schedule:

.github/workflows/test_frameworks.yml

@@ -3,7 +3,7 @@ name: Framework tests
 on:
   push:
     branches:
-      - 2.x
+      - main
   pull_request:
 
 concurrency:

README.md

@@ -1,6 +1,6 @@
 # `ddtrace`
 
-[![CircleCI](https://circleci.com/gh/DataDog/dd-trace-py/tree/2.x.svg?style=svg)](https://circleci.com/gh/DataDog/dd-trace-py/tree/2.x)
+[![CircleCI](https://circleci.com/gh/DataDog/dd-trace-py/tree/main.svg?style=svg)](https://circleci.com/gh/DataDog/dd-trace-py/tree/main)
 [![PypiVersions](https://img.shields.io/pypi/v/ddtrace.svg)](https://pypi.org/project/ddtrace/)
 [![Pyversions](https://img.shields.io/pypi/pyversions/ddtrace.svg?style=flat)](https://pypi.org/project/ddtrace/)
 

docs/upgrading.rst

@@ -32,7 +32,7 @@ Before v0.60.0, you must enable all deprecation warnings and filter the applicat
 
 .. _upgrade-0.x:
 
-Upgrade to 1.x
+Upgrade to 1.0
 **************
 
 Environment variables
@@ -51,7 +51,7 @@ Use the following patterns to identify the deprecated environment variables in a
 
 .. _upgrade-1.x:
 
-Upgrade to 2.x
+Upgrade to 2.0
 **************
 
 Environment variables

releasenotes/config.yaml

@@ -1,5 +1,5 @@
 ---
-default_branch: origin/2.x
+default_branch: origin/main
 unreleased_version_title: Unreleased
 sections:
   # The prelude section is implicitly included.