fix: EIO expects us to pin main for read-vault-secrets

Signed-off-by: Matt Trachier <matt.trachier@suse.com>

Author: matttrach

.github/workflows/fossa.yml

@@ -20,7 +20,7 @@ jobs:
     # The FOSSA token is shared between all repos in Rancher's GH org. It can be
     # used directly and there is no need to request specific access to EIO.
     - name: Read FOSSA token
-      uses: rancher-eio/read-vault-secrets@0da85151ad1f19ed7986c41587e45aac1ace74b6 # v3
+      uses: rancher-eio/read-vault-secrets@main
       with:
         secrets: |
           secret/data/github/org/rancher/fossa/push token | FOSSA_API_KEY_PUSH_ONLY