CI: Remove ruby < 3.2 from test matrix on Windows

Ruby < 3.2 is not compatible to gcc-15 and patches will not be backported since it's EOL now.
Unfortunately MSYS2 is a rolling release with no option for an older gcc.
Althought setup-ruby installs an older gcc-14.2 package by default, it fails to install further packages per pacman due to dependencies:

```sh
  $ pacman.exe -Sy --noconfirm --noprogressbar --needed --disable-download-timeout  mingw-w64-x86_64-postgresql
  resolving dependencies...
  looking for conflicting packages...
  error: failed to prepare transaction (could not satisfy dependencies)
  :: installing mingw-w64-x86_64-gcc-libs (15.1.0-8) breaks dependency 'mingw-w64-x86_64-gcc-libs=14.2.0-3' required by mingw-w64-x86_64-gcc
```

Author: larskanis

.github/workflows/binary-gems.yml

@@ -63,14 +63,14 @@ jobs:
       matrix:
         include:
           - os: windows-latest
-            ruby: "3.3"
+            ruby: "3.4"
             platform: "x64-mingw-ucrt"
           - os: windows-latest
-            ruby: "3.1.4-1"
+            ruby: "3.2.9-1"
             platform: "x86-mingw32"
             PGVERSION: 10.20-1-windows
           - os: windows-latest
-            ruby: "2.7"
+            ruby: "3.2"
             platform: "x64-mingw32"
             PGVERSION: 16.6-1-windows-x64
           - os: ubuntu-latest
@@ -135,7 +135,6 @@ jobs:
           echo "PGPASSWORD="  | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
 
       - run: echo $env:PATH
-      - run: gem update --system 3.3.26
       - run: bundle install
       - run: gem install --local pg-*${{ matrix.platform }}.gem --verbose
       - name: Run specs

.github/workflows/source-gem.yml

@@ -47,7 +47,7 @@ jobs:
             PGVERSION: 17.0-1-windows-x64
             PGVER: "17"
           - os: windows
-            ruby: "2.7"
+            ruby: "3.2"
             PGVERSION: 10.20-1-windows-x64
             PGVER: "10"
           - os: windows
@@ -131,7 +131,6 @@ jobs:
           sudo mv /Library/PostgreSQL/$PGVER/pgsql/* /Library/PostgreSQL/$PGVER/ && \
           echo /Library/PostgreSQL/$PGVER/bin >> $GITHUB_PATH
 
-      - run: gem update --system 3.3.26
       - run: bundle install
 
       - run: gem install --local *.gem --verbose