Fix `check` stage of `PKGBUILD` [ci skip]

pkg/aur/PKGBUILD.in

@@ -19,7 +19,7 @@ build() {
 }
 
 check() {
-    local pyver=$(python -c 'import sys; print("{}.{}".format(*sys.version_info[:2]))')
+    local pyver=$(python -c 'import sys; print(sys.implementation.cache_tag)')
     local machine=$(python -c 'import platform; print(platform.machine())')
     cd "${srcdir}/${_name}-${pkgver}/build/lib.linux-${machine}-${pyver}"
     python -m unittest ${_name}.tests