[github] skip perl 5.40 on windows (broken compiler)

Same issue as cff3c3c; somehow this gcc doesn't recognize %zu as
used in core headers/macros.

Author: mauke

.github/workflows/run-tests.yml

@@ -20,6 +20,7 @@ jobs:
           - { os: windows-latest, perl-version: "5.24" }
           - { os: windows-latest, perl-version: "5.26" }
           - { os: windows-latest, perl-version: "5.38" }
+          - { os: windows-latest, perl-version: "5.40" }
 
     runs-on: ${{ matrix.os }}
     name: "perl v${{ matrix.perl-version }} on ${{ matrix.os }}"

.github/workflows/run-tests.yml.tmpl

@@ -20,6 +20,7 @@ jobs:
           - { os: windows-latest, perl-version: "5.24" }
           - { os: windows-latest, perl-version: "5.26" }
           - { os: windows-latest, perl-version: "5.38" }
+          - { os: windows-latest, perl-version: "5.40" }
 
     runs-on: ${{ matrix.os }}
     name: "perl v${{ matrix.perl-version }} on ${{ matrix.os }}"