add release documentation, meta file in gitignore

Author: mediumTaj

.gitignore

@@ -66,3 +66,4 @@ exclude-filter.txt.meta
 /Travis/README.md.meta
 /Travis/runTests.sh.meta
 /Travis/TravisBuild.cs.meta
+Docs/publishing-release.md.meta

Docs/publishing-release.md

@@ -0,0 +1,20 @@
+The following tasks should be completed before publishing a release. Track the progress of the release by copying and pasting the tasks below into an issue for the release.
+
+#### Github and Project Planning
+
+- [ ] Review and merge any outstanding pull requests.
+- [ ] Review any oustanding issues assigned to this release milestone.
+- [ ] Branch from `develop` to `rc-[version]`, ex: `rc-2.0.0`.
+- [ ] Draft release with version in the format of `v2.0.0` targeting the 'master' branch. Standard release should be named using the format `Watson Developer Cloud Unity SDK [version]`, ex: `Watson Developer Cloud Unity SDK v2.0.0`.
+ 
+#### Source Changes (in `rc` branch)
+
+- [ ] Update changelog.
+- [ ] Update `PROJECT_NUMBER` in `Doxyfile` to current version.
+- [ ] Update `SDK_VERSION` in `src/IBM.WatsonDeveloperCloud/Constants.cs`
+
+#### Publish Release
+
+- [ ] Create a pull request to merge `rc` branch to `master`. After all checks have passed, merge the PR.
+- [ ] Publish release.
+- [ ] Create a pull request to merge `rc` branch into the `development` branch.