Update publish-all so it commits on a different branch.

This allows to open a PR for the changes to be submitted on the
repository, instead of silently pushing to master.

cranelift/publish-all.sh

@@ -33,9 +33,11 @@ cargo update
 #
 # Note that libraries need to be published in topological order.
 
+echo git checkout -b bump-version-to-$version
 echo git commit -a -m "\"Bump version to $version"\"
 echo git tag v$version
-echo git push
+echo git push origin bump-version-to-$version
+echo "# Don't forget to click the above link to open a pull-request!"
 echo git push origin v$version
 for crate in \
     entity bforest codegen/shared codegen/meta codegen frontend native \