Add release instructions for opentelemetry proto. (#133)

* Add release instructions for opentelemetry proto.

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

* Add changelog and vscode settings

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

Author: bogdandrutu

.vscode/settings.json

@@ -0,0 +1,12 @@
+{
+    "rewrap.wrappingColumn": 80,
+    "editor.rulers": [80],
+    "markdownlint.config": {
+        "MD004": false,
+        "MD013": false,
+        "MD024": {"allow_different_nesting": true},
+        "MD029": {"style": "ordered"},
+        "MD033": false,
+        "MD040": false,
+    },
+}

CHANGELOG.md

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+# Changelog
+
+## Unreleased
+
+- Initial protos for trace, metrics, resource and OTLP.

RELEASING.md

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+# How to Create a Release of OpenTelemetry Proto (for Maintainers Only)
+
+## Tagging the Release
+
+Our release branches follow the naming convention of `v<major>.<minor>.x`, while
+the tags include the patch version `v<major>.<minor>.<patch>`. For example, the
+same branch `v0.3.x` would be used to create all `v0.3` tags (e.g. `v0.3.0`,
+`v0.3.1`).
+
+In this section upstream repository refers to the main opentelemetry-proto
+github repository.
+
+Before any push to the upstream repository you need to create a [personal access
+token](https://help.github.com/articles/creating-a-personal-access-token-for-the-command-line/).
+
+1. Create the release branch and push it to GitHub:
+
+    ```bash
+    MAJOR=0 MINOR=3 PATCH=0 # Set appropriately for new release
+    git checkout -b v$MAJOR.$MINOR.x master
+    git push upstream v$MAJOR.$MINOR.x
+    ```
+
+2. Enable branch protection for the new branch, if you have admin access.
+   Otherwise, let someone with admin access know that there is a new release
+   branch.
+
+    - Open the branch protection settings for the new branch, by following
+      [Github's instructions](https://help.github.com/articles/configuring-protected-branches/).
+    - Copy the settings from a previous branch, i.e., check
+      - `Protect this branch`
+      - `Require pull request reviews before merging`
+      - `Require status checks to pass before merging`
+      - `Include administrators`
+
+      Enable the following required status checks:
+      - `cla/linuxfoundation`
+      - `ci/circleci: build`
+    - Uncheck everything else.
+    - Click "Save changes".
+
+3. For `vMajor.Minor.x` branch:
+
+    - Create and push a tag:
+
+    ```bash
+    git checkout v$MAJOR.$MINOR.x
+    git pull upstream v$MAJOR.$MINOR.x
+    git tag -a v$MAJOR.$MINOR.$PATCH -m "Version $MAJOR.$MINOR.$PATCH"
+    git push upstream v$MAJOR.$MINOR.x
+    ```
+
+## Patch Release
+
+All patch releases should include only bug-fixes, and must avoid
+adding/modifying the public APIs. To cherry-pick one commit use the following
+instructions:
+
+- Create and push a tag:
+
+```bash
+COMMIT=1224f0a # Set the right commit hash.
+git checkout -b cherrypick v$MAJOR.$MINOR.x
+git cherry-pick -x $COMMIT
+git commit -a -m "Cherry-pick commit $COMMIT"
+```
+
+- Go through PR review and merge it to GitHub v$MAJOR.$MINOR.x branch.
+
+- Tag a new patch release when all commits are merged.
+
+## Announcement
+
+Once deployment is done, go to Github [release
+page](https://github.com/open-telemetry/opentelemetry-proto/releases), press
+`Draft a new release` to write release notes about the new release.
+
+You can use `git log upstream/v$MAJOR.$((MINOR-1)).x..upstream/v$MAJOR.$MINOR.x --graph --first-parent`
+or the Github [compare tool](https://github.com/open-telemetry/opentelemetry-proto/compare/)
+to view a summary of all commits since last release as a reference.
+
+In addition, you can refer to
+[CHANGELOG.md](https://github.com/open-telemetry/opentelemetry-proto/blob/master/CHANGELOG.md)
+for a list of major changes since last release.
+
+## Update release versions in documentations and CHANGELOG files
+
+After releasing is done, you need to update
+[README.md](https://github.com/open-telemetry/opentelemetry-proto/blob/master/README.md) and
+[CHANGELOG.md](https://github.com/open-telemetry/opentelemetry-proto/blob/master/CHANGELOG.md).
+
+Create a PR to mark the new release in
+[CHANGELOG.md](https://github.com/census-instrumentation/opencensus-java/blob/master/CHANGELOG.md)
+on master branch.