ci: skip unsupported latest CLI and Postgres 14 combination (#454)

The v1.7.2 release E2E run fails when the latest CLI starts PostgreSQL
14: the current Storage migration uses SQL unsupported by PostgreSQL 14.
This combination is already excluded from the v2 and v3 action matrices.

Exclude only `latest` with PostgreSQL 14 from the v1 release matrix.
Pinned CLI versions continue testing PostgreSQL 14, and the latest CLI
continues testing PostgreSQL 15 and 17.

.github/workflows/start.yml

@@ -33,6 +33,8 @@ jobs:
         exclude:
           - version: 1.178.2
             pg_major: 17
+          - version: latest
+            pg_major: 14
     steps:
       - uses: actions/checkout@v4
       - uses: ./