Update guide-release-process-0.75.md

Fix command to get the base version, currently broken if a patch for a previous version was released in between release candidates (e.g. in case of release sequence 0.78-rc0, 0.77.1, 0.78-rc1 then 0.77.1 would be incorrectly picked as base version for 0.78-rc2 instead of 0.78-rc1).

docs/guide-release-process-0.75.md

@@ -226,7 +226,7 @@ git switch main
 git fetch --all --tags
 git pull
 
-BASE_VERSION=$(git tag --sort=-creatordate  | grep -E '^v0\.' | head -n2 | tail -n1)
+BASE_VERSION=$(git tag -l --sort=-v:refname | grep -E '^v0\.' | head -n2 | tail -n1)
 
 # Generate the changelog
 npx @rnx-kit/rn-changelog-generator \