build-packages: More lenient permissions on the packages directory

We don't really the more restrictive `700` since all these artefacts
are public anyway, and this breaks the current release workflow,
so let's go with `755` instead.

Author: rgacogne

.github/workflows/build-packages.yml

@@ -247,6 +247,6 @@ jobs:
           echo "$SSHKEY" > ~/.ssh/id_ed25519
           chmod 600 ~/.ssh/id_ed25519
           echo "$HOSTKEY" > ~/.ssh/known_hosts
-          mkdir -m 700 -p "slsa/${PRODUCT}/${VERSION}/"
+          mkdir -m 755 -p "slsa/${PRODUCT}/${VERSION}/"
           mv ${{steps.download-provenance.outputs.download-path}}/*.jsonl "slsa/${PRODUCT}/${VERSION}"
           rsync -4rlptD slsa/* "$RSYNCTARGET"