Scripts for releasing. (#576)

* Scripts for releasing.

- fixes #510

* fix review comments.

Co-authored-by: Joshua MacDonald <jmacd@users.noreply.github.com>

RELEASING.md

@@ -0,0 +1,36 @@
+# Release Process
+
+## Pre-Release
+Update go.mod for submodules to depend on the new release which will happen
+in the next step. This will create build failure for those who depend
+on the master branch instead or released version. But they shouldn't be
+depending on the master. So it is not a concern.
+
+1. Run the pre-release script. It creates a branch pre_release_<tag> to make the changes.
+2. Verify the changes.
+3. Push the changes to upstream.
+4. Create a PR on github and merge the PR once approved.
+
+    ```
+    ./pre-release.sh -t <new tag>
+    git diff master
+    git push
+    ```
+
+
+## Tag
+Now create a new Tag on the commit hash of the changes made in pre-release step.
+Use the same tag as used in the pre-release step.
+
+1. Run the tag.sh script.
+2. Push tags upstream. Make sure you run this for all sub-modules as well.
+
+    ```
+    ./tag.sh -t <new tag> -c <commit-hash>
+    git push upstream <new tag>
+    git push upstream <submodules-path/new tag>
+    ```
+
+## Release
+Now create a release for the new tag on github. tag.sh script generates commit logs since
+last release. Use that to draft the new release.