ci: bump riscv64-linux-debug timeout by 1 hour

A very recent change seems to have made this slower.

Author: alexrp

.forgejo/workflows/ci.yaml

@@ -88,7 +88,7 @@ jobs:
           fetch-depth: 0
       - name: Build and Test
         run: sh ci/riscv64-linux-debug.sh
-        timeout-minutes: 540
+        timeout-minutes: 600
   riscv64-linux-release:
     if: github.event_name != 'pull_request'
     runs-on: [self-hosted, riscv64-linux]