Retry sccache release downloads

.gitea/actions/rust-cache/action.yml

@@ -79,8 +79,16 @@ runs:
         base_url="https://github.com/mozilla/sccache/releases/download/${version}"
         tmp="$(mktemp -d)"
         trap 'rm -rf "$tmp"' EXIT
-        curl -fsSLo "$tmp/$asset" "$base_url/$asset"
-        curl -fsSLo "$tmp/$asset.sha256" "$base_url/$asset.sha256"
+        curl_retry() {
+          curl --http1.1 --retry 5 --retry-all-errors --retry-delay 3 --connect-timeout 20 -fsSLo "$1" "$2"
+        }
+        if ! curl_retry "$tmp/$asset" "$base_url/$asset" || ! curl_retry "$tmp/$asset.sha256" "$base_url/$asset.sha256"; then
+          echo "sccache release download failed; falling back to cargo install" >&2
+          crate_version="${version#v}"
+          cargo install sccache --locked --version "$crate_version" --features s3
+          sccache --version
+          exit 0
+        fi
         expected="$(tr -d '[:space:]' < "$tmp/$asset.sha256")"
         if command -v sha256sum >/dev/null 2>&1; then
           actual="$(sha256sum "$tmp/$asset" | cut -d ' ' -f 1)"