Upgrade GitHub Actions workflow

[fdcastel]

Closes #156

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Key improvements:

1. No full PostgreSQL build from source - x64 uses prebuilt EDB binaries (PG 17.9 binary archive, ~1 min download vs ~15 min build)
2. x86 libpq only - Builds ONLY the libpq client library from source via meson compile ... libpq:shared_library. The test server is always x64; x86 libpq is only needed to compile/link the x86 ODBC driver. No SSL needed since CI tests use localhost.
3. Eliminated dependencies: Win32/Win64 OpenSSL and pkgconfiglite are no longer needed (winflexbison is still required by PG's meson build system)
4. Parallel matrix - standard and mimalloc run simultaneously
5. Separate release job - only runs on version tags

Results (first run, no caches):

• standard: 8m28s
• mimalloc: 11m47s
• Total wall-clock: ~12 min (vs ~25+ min sequential in the old workflow)

Subsequent cached runs will be even faster since the x86 libpq, x64 binaries, and all tools are cached.

[davecramer]

I believe we do require openssl to release a version.

[davecramer]

The reason we pull from git is to get the latest. 17.9 is not the latest. We can cache the build though

[fdcastel]

Sorry Dave. I have to admit I didn’t pay much attention to the release process. I focused mainly on the builds in this initial PR to get some early feedback.

I’ll review how the current release process works and come back with a revised PR.

[fdcastel]

@davecramer I've updated the PR to address both of your concerns.

Please feel free to share any additional questions or suggestions.

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What changed:

1. OpenSSL restored — Both x64 and x86 builds now include OpenSSL (currently 3.3.6, matching main). The SSL DLLs are placed into d:\postgresql\bin and d:\postgresql86\bin so the installers pick them up correctly.

2. PostgreSQL built from source (REL_18_STABLE) — No more prebuilt binaries. The full x64 server is built with ninja + ninja install (same as before), and pkgconfiglite is back for OpenSSL detection.

3. Rebased on latest main — Includes the release 17.00.0008 changes and the OpenSSL 3.3.6 CVE fix.

What's kept from the original PR:

• Parallel matrix — standard and mimalloc run simultaneously
• Separate release job — only runs on REL-* tags, uses upload-artifact/download-artifact
• Minimal x86 libpq build — only builds the client library (with SSL now), not the full server. Much faster than a full x86 build.

What's new:

• Dedicated build-postgres job — Builds PostgreSQL x64 (full) and x86 (libpq only) once, caches the result. Both matrix jobs then restore from cache using actions/cache/restore. This avoids wasteful duplicate PG builds and speeds up cache-miss debugging runs.

• workflow_dispatch trigger — Allows manual workflow runs from the Actions tab (useful for debugging).

Workflow structure:

build-postgres          →  build-and-test (standard)   →  release
(PG x64 full + x86 libpq)    build-and-test (mimalloc)      (only on REL-* tags)

Timing (cached run on my fork):

Job	Duration
build-postgres	10s (cache hit)
build-and-test (standard)	~7m
build-and-test (mimalloc)	~8m
Total wall-clock	~9 min

On a cold run (no cache), build-postgres will take longer to build PG from source, but the result is cached for all subsequent runs. The WORKFLOW_VERSION_POSTGRESQL env var can be bumped to invalidate the cache when needed.

[davecramer]

Just confirmed that the release still works, thanks so much for this