doc: udpate release instructions

Author: opqdonut

docs/11_developer_guide.md

@@ -12,6 +12,6 @@
 
 1. Update `CHANGELOG.md`
 2. Set the appropriate version in `project.clj` and commit and push.
-3. Run `./scripts/release.sh`
+3. Create a release on github: https://github.com/metosin/spec-tools/releases
 
 The actual building of the release artifact is done by the CI service.