Add FLINT 3.4.0 to test matrix

Author: oscarbenjamin

.github/workflows/buildwheel.yml

@@ -307,7 +307,13 @@ jobs:
       fail-fast: false
       matrix:
         # Supported Flint versions:
-        flint-tag: ['v3.0.1', 'v3.1.3-p1', 'v3.2.2', 'v3.3.1']
+        flint-tag: [
+          'v3.0.1',
+          'v3.1.3-p1',
+          'v3.2.2',
+          'v3.3.1',
+          'v3.4.0',
+        ]
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with: