Update release notes for 1.15.1 release

CHANGELOG.md

@@ -1,3 +1,14 @@
+## Version 1.15.1 (2021/07/20)
+
+### Pull Requests Merged
+
+#### Bugs fixed
+
+* [PR 81](https://github.com/pytroll/trollimage/pull/81) - Fix Colormap not being able to merge RGB and RGBA colormaps ([1658](https://github.com/pytroll/satpy/issues/1658))
+
+In this release 1 pull request was closed.
+
+
 ## Version 1.15.0 (2021/03/12)
 
 ### Issues Closed

RELEASING.md

@@ -5,19 +5,42 @@
 3. run the unittests
 4. run `loghub` and update the `CHANGELOG.md` file:
 
-```
-loghub pytroll/trollimage -u <username> -st v0.8.0 -plg bug "Bugs fixed" -plg enhancement "Features added" -plg documentation "Documentation changes" -plg backwards-incompatibility "Backwards incompatible changes"
-```
+   ```
+   loghub pytroll/trollimage --token $LOGHUB_GITHUB_TOKEN -st v<previous version> -plg bug "Bugs fixed" -plg enhancement "Features added" -plg documentation "Documentation changes" -plg backwards-incompatibility "Backward incompatible changes" -plg refactor "Refactoring"
+   ```
 
-Don't forget to commit!
+   This uses a `LOGHUB_GITHUB_TOKEN` environment variable. This must be created
+   on GitHub and it is recommended that you add it to your `.bashrc` or
+   `.bash_profile` or equivalent.
+
+   This command will create a CHANGELOG.temp file which needs to be added
+   to the top of the CHANGLOG.md file.  The same content is also printed
+   to terminal, so that can be copy-pasted, too.  Remember to update also
+   the version number to the same given in step 5. Don't forget to commit
+   CHANGELOG.md!
+   ```
 
 5. Create a tag with the new version number, starting with a 'v', eg:
 
-```
-git tag -a v0.22.45 -m "Version 0.22.45"
-```
+   ```
+   git tag -a v0.22.45 -m "Version 0.22.45"
+   ```
+
+   For example if the previous tag was `v0.9.0` and the new release is a
+   patch release, do:
+
+   ```
+   git tag -a v0.9.1 -m "Version 0.9.1"
+   ```
 
-See [semver.org](http://semver.org/) on how to write a version number.
+   See [semver.org](http://semver.org/) on how to write a version number.
 
 6. push changes to github `git push --follow-tags`
-7. Verify travis tests passed and deployed sdist and wheel to PyPI
+7. Verify github action unittests passed.
+8. Create a "Release" on GitHub by going to
+   https://github.com/pytroll/trollimage/releases and clicking "Draft a new release".
+   On the next page enter the newly created tag in the "Tag version" field,
+   "Version X.Y.Z" in the "Release title" field, and paste the markdown from
+   the changelog (the portion under the version section header) in the
+   "Describe this release" box. Finally click "Publish release".
+9. Verify the GitHub actions for deployment succeed and the release is on PyPI.