chore(dev): Add DEPRECATIONS.md file to track deprecations (#18613)

* chore(dev): Add DEPRECATIONS.md file to track deprecations

Add a file to track deprecations through their lifecycle and remind us to come back to take any
deprecation actions as part of each release.

See #14983 for the process proposal. The intent is to
make sure we follow through on deprecations, migrations, and removals.

Closes: #14983

Signed-off-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>

* Update process in DEPRECATION.md too

Signed-off-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>

* Remove from "to be removed"

Will instead be added once the migration step is complete

Signed-off-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>

* Fix markdown headers and add link to process

Signed-off-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>

---------

Signed-off-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>

.github/ISSUE_TEMPLATE/minor-release.md

@@ -7,6 +7,8 @@ labels: "domain: releasing"
 
 The week before the release:
 
+- [ ] Check for any outstanding deprecation actions in [DEPRECATIONS.md](docs/DEPRECATIONS.md) and
+      take them (or have someone help you take them)
 - [ ] Create a new release branch from master to freeze commits
   - `git fetch && git checkout origin/master && git checkout -b v0.<new version number> && git push -u`
 - [ ] Create a new release preparation branch from `master`

docs/DEPRECATION.md

@@ -78,10 +78,12 @@ When introducing a deprecation into Vector, the pull request introducing the dep
   the new name will be appended with the text `(formerly OldName)`.
 - Add a log message to Vector that is logged at the `WARN` level starting with the word `DEPRECATION` if Vector detects
   the deprecated configuration or feature being used (when possible).
+- Add the deprecation to [DEPRECATIONS.md](docs/DEPRECATIONS.md) to track migration (if applicable) and removal
 
 When removing a deprecation in a subsequent release, the pull request should:
 
 - Indicate that it is a breaking change by including `!` in the title after the type/scope
 - Remove the deprecation from the documentation
 - Add a note to the Breaking Changes section of the upgrade guide for the next release with a description and directions
   for transitioning if applicable.
+- Remove the deprecation from [DEPRECATIONS.md](docs/DEPRECATIONS.md)

docs/DEPRECATIONS.md

@@ -0,0 +1,9 @@
+See [DEPRECATION.md](docs/DEPRECATION.md#process) for the process for updating this file.
+
+## To be deprecated
+
+## To be migrated
+
+* legacy_openssl_provider v0.33.0 OpenSSL legacy provider flag should default to false
+
+## To be removed