bump ifort to 2021.12

Author: perazz

.github/workflows/CI.yml

@@ -26,7 +26,7 @@ jobs:
           - {compiler: gcc, version: 12}
           - {compiler: gcc, version: 13}
           - {compiler: intel, version: '2024.1'}
-          - {compiler: intel-classic, version: '2021.9'}
+          - {compiler: intel-classic, version: '2021.12'}
         build: [cmake]
         include:
           - os: ubuntu-latest
@@ -35,7 +35,7 @@ jobs:
               - {compiler: gcc, version: 10}
         exclude:
           - os: macos-13
-            toolchain: {compiler: intel-classic, version: '2021.9'}
+            toolchain: {compiler: intel-classic, version: '2021.12'}
           - os: macos-13
             toolchain: {compiler: intel, version: '2024.1'}
           - os: macos-13