Update the docs and add kgcl diff to release pipeline

docs/developers/release.md

@@ -40,7 +40,7 @@ EDIT: As of today (Wed 5 Oct, 2022), this does not work without passing a GitHub
     - tmp/hpoa/phenotype_annotation_negated.tab
     - tmp/hpoa/phenotype_annotation.tab
     - tmp/hpoa/phenotype_to_genes.txt
-7. ALT2: If you have `gh` installed, you can use the following pipeline: `make public_release GHVERSION=v2022-10-05` (no `sh run.sh`!). This will automate the above step (6). When the draft release is successfully created, you should see a link in your console, like `https://github.com/obophenotype/human-phenotype-ontology/releases/tag/untagged-a230b72fb7457a460e79` (final line of output).  Go to this link with your browser. Edit the draft release in whatever way you wish. 
+7. ALT2: If you have `gh` installed, you can use the following pipeline: `make public_release GHVERSION=v2022-10-05` (no `sh run.sh`!). This will automate the above step (6). When the draft release is successfully created, you should see a link in your console, like `https://github.com/obophenotype/human-phenotype-ontology/releases/tag/untagged-a230b72fb7457a460e79` (final line of output).  Go to this link with your browser. Edit the draft release in whatever way you wish. Usually you want to copy the contents from reports/difference_release_base.md into the description.
 8. Click on `Publish release`. 
 9. Add to the release notes in github
 10. announce on hpo-mailing list (groups.io) - this is the most important part, where we have to take a bit of time to formulate the mail and align with Peter, Nicole, etc. (all the people that actively worked on hpo for this release)

src/ontology/hp.Makefile

@@ -362,6 +362,8 @@ KGCL_ONTOLOGY=hp-base.obo
 upgrade_oak:
 	pip install -U oaklib
 
+prepare_release: kgcl-diff
+
 .PHONY: kgcl-diff
 kgcl-diff: kgcl-diff-release-base