Use self-repo syntax for all in-repo actions/reusable workflows (#1024)

With the self-repo syntax, we also shouldn't need any of these
`actions/checkout` calls.

Signed-off-by: William Woodruff <william@yossarian.net>

---------

Signed-off-by: William Woodruff <william@yossarian.net>

.github/workflows/release.yml

@@ -116,7 +116,7 @@ jobs:
     name: Update docs
     needs:
       - release
-    uses: ./.github/workflows/update-docs.yml
+    uses: $/.github/workflows/update-docs.yml
     permissions:
       contents: write
       pull-requests: write