Upgrade sqlc to 1.31.0 (#1222)

I just noticed that we got a rare release of sqlc yesterday [1] and
figured I'd upgrade things to make sure they still work. Very little
changed, but we did get a couple tiny fixes in SQLite.

[1] https://github.com/sqlc-dev/sqlc/releases/tag/v1.31.0

Author: brandur

.github/workflows/ci.yaml

@@ -341,7 +341,7 @@ jobs:
       - name: Setup sqlc
         uses: sqlc-dev/setup-sqlc@v5
         with:
-          sqlc-version: "1.30.0"
+          sqlc-version: "1.31.0"
 
       - name: Verify migrations match
         run: |