Add newly supported actions

Adds newly supported actions (`shellcheck`,
`build-and-inspect-python-package` and `file-existence-action`)

Signed-off-by: Liran Rotenberg <[email protected]>

Author: liranr23

docs/github-actions-providers.md

@@ -9,6 +9,9 @@
 * `rojopolis/spellcheck-github-actions@*` - Spellcheck action
 * `sigstore/gh-action-sigstore-python@*` - Sigstore Python action
 * `step-security/harden-runner@*` - Harden Runner action
+* `ludeeus/action-shellcheck@*` - Shellcheck action
+* `hynek/build-and-inspect-python-package@*` - Build and inspect Python package action
+* `andstor/file-existence-action@*` - File existence action
 
 ## Denied Providers