Drop the faraday 1 test matrix and stop cancelling sibling legs

The matrix passed FARADAY_VERSION to a Gemfile line that read it:

    gem 'faraday', ENV['FARADAY_VERSION'] if ENV['FARADAY_VERSION'].to_s != ''

That line was removed in 9ddb870 (#129) in September 2022, so nothing
has consumed the variable since; the three "faraday 1.x" legs have been
running an identical bundle to the plain legs and reporting coverage
artifacts under a name that claims otherwise.

Faraday 1 also can't be installed here any more: the gemspec requires
faraday-net_http_persistent '~> 2.0', which requires faraday '~> 2.5',
and faraday-retry '~> 2.2' is 2.x only. So the leg advertises coverage
that is no longer possible rather than merely redundant.

Also sets fail-fast: false. The matrix relied on the default, true, so
the first leg to fail cancelled the other five and their results were
never reported -- which made a repository-wide failure look like it only
affected one Ruby version.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: 2 people

.github/workflows/ruby.yml

@@ -18,9 +18,9 @@ jobs:
   test:
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false # One failing Ruby shouldn't cancel the others
       matrix:
         ruby: [3.2, 3.3, 3.4]
-        faraday_version: ['', '~> 1.0'] # Defaults to whatever's the most recent version.
     steps:
     - uses: actions/checkout@v6
 
@@ -29,16 +29,12 @@ jobs:
       with:
         ruby-version: ${{ matrix.ruby }}
         bundler-cache: true
-      env:
-        FARADAY_VERSION: ${{ matrix.faraday_version }}
 
-    - name: "Run tests for Ruby ${{ matrix.ruby }} and Faraday ${{ matrix.faraday_version == '~> 1.0' && '1.x' || 'latest' }}"
+    - name: "Run tests for Ruby ${{ matrix.ruby }}"
       run: bundle exec rake spec
-      env:
-        FARADAY_VERSION: ${{ matrix.faraday_version }}
 
     - name: Upload coverage artifacts
       uses: actions/upload-artifact@v6
       with:
-        name: "coverage-${{ matrix.ruby }}-${{ matrix.faraday_version == '~> 1.0' && 'faraday-1.x' || 'faraday-latest' }}"
+        name: "coverage-${{ matrix.ruby }}"
         path: coverage/