Switch macos-latest to macos-14

The build on macos-latest (currently macos-15) segfaults due to what I
suspect to be an issue with the SoftHSM2 build distributed on Homebrew.
To be investigated.

Author: MatthiasValvekens

.github/workflows/release.yml

@@ -73,7 +73,7 @@ jobs:
           - ubuntu-latest
           - ubuntu-24.04-arm
           - windows-latest
-          - macos-latest
+          - macos-14
     steps:
       - uses: actions/checkout@v4
       - name: Setup Python

.github/workflows/tests.yml

@@ -20,7 +20,7 @@ jobs:
         os:
           - ubuntu-latest
           - windows-latest
-          - macos-latest
+          - macos-14
         python-version:
           - "3.9"
           - "3.10"
@@ -36,7 +36,7 @@ jobs:
           - pkcs11-platform: opencryptoki
             os: windows-latest
           - pkcs11-platform: opencryptoki
-            os: macos-latest
+            os: macos-14
     steps:
       - name: Acquire sources
         uses: actions/checkout@v4