[use proper (?) ninja apk package]

Author: kinke

.github/workflows/main.yml

@@ -134,7 +134,7 @@ jobs:
           else
             # set up Alpine container
             apk add \
-              git cmake ninja g++ ldc llvm-dev llvm-static compiler-rt \
+              git cmake ninja-is-really-ninja g++ ldc llvm-dev llvm-static compiler-rt \
               libxml2-static zstd-static zlib-static \
               bash grep diffutils make curl 7zip
             # create missing 7za symlink