gh-actions clang-qemu: add versions 21 & 22 for loong64

Author: mr-c

.github/workflows/ci.yml

@@ -84,6 +84,16 @@ jobs:
           arch_deb: loong64
           arch_gnu: loongarch64
           distro: ubuntu-24.04
+        - version: 21
+          cross: loongarch64
+          arch_deb: loong64
+          arch_gnu: loongarch64
+          distro: ubuntu-24.04
+        - version: 22
+          cross: loongarch64
+          arch_deb: loong64
+          arch_gnu: loongarch64
+          distro: ubuntu-24.04
     runs-on: ${{ matrix.distro }}
     steps:
     - uses: actions/checkout@v6