.github/workflows/compilers.yml: clang-13

LLVM made release/122.x branch.  Its master is now version 12.

.github/workflows/compilers.yml

@@ -54,7 +54,8 @@ jobs:
 #         - { key: default_cc, name: gcc-6,     value: gcc-6 }
 #         - { key: default_cc, name: gcc-5,     value: gcc-5 }
           - { key: default_cc, name: gcc-4.8,   value: gcc-4.8 }
-          - { key: default_cc, name: clang-12,  value: clang-12 }
+          - { key: default_cc, name: clang-13,  value: clang-13 }
+#         - { key: default_cc, name: clang-12,  value: clang-12 }
 #         - { key: default_cc, name: clang-11,  value: clang-11 }
 #         - { key: default_cc, name: clang-10,  value: clang-10 }
 #         - { key: default_cc, name: clang-9,   value: clang-9 }