Used CI from laminas/ to avoid repeated effort

Note: this removes BC checks, which are currently not running for PHP 8.x

Ref: laminas/laminas-ci-matrix-action#59
Ref: laminas/laminas-ci-matrix-action#60
Ref: Roave/BackwardCompatibilityCheck#283
Ref: Roave/BetterReflection#701

.github/workflows/demo-scripts.yml → .github/workflows/continuous-integration.yml

@@ -1,10 +1,38 @@
-name: "Check Demo Scripts"
+# See https://github.com/laminas/laminas-continuous-integration-action
+# Generates a job matrix based on current dependencies and supported version
+# ranges, then runs all those jobs
+name: "Continuous Integration"
 
 on:
   pull_request:
   push:
 
 jobs:
+  matrix:
+    name: Generate job matrix
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.matrix.outputs.matrix }}
+    steps:
+      - name: Gather CI configuration
+        id: matrix
+        uses: laminas/laminas-ci-matrix-action@1.10.0
+
+  qa:
+    name: QA Checks
+    needs: [ matrix ]
+    runs-on: ${{ matrix.operatingSystem }}
+    strategy:
+      fail-fast: false
+      matrix: ${{ fromJSON(needs.matrix.outputs.matrix) }}
+    steps:
+      - name: ${{ matrix.name }}
+        uses: laminas/laminas-continuous-integration-action@1.12.0
+        env:
+          "GITHUB_TOKEN": ${{ secrets.GITHUB_TOKEN }}
+        with:
+          job: ${{ matrix.job }}
+
   demo-scripts:
     name: "Check Demo Scripts"