CI: enabled plugins

.github/workflows/build.yml

@@ -20,7 +20,7 @@ jobs:
       env:
         CXX: ${{ matrix.compiler }}
       run: |
-        cmake -DBUILD_TESTING=ON -DBUILD_LIB=ON ..
+        cmake -DBUILD_TESTING=ON -DBUILD_LIB=ON -DBUILD_PLUGIN=ON ..
         make -j4
     - name: Run tests
       working-directory: build
@@ -49,7 +49,7 @@ jobs:
     - name: Compile tests
       working-directory: build
       run: |
-        cmake -DBUILD_TESTING=ON -DBUILD_LIB=ON ${{ matrix.toolset_option }} ..
+        cmake -DBUILD_TESTING=ON -DBUILD_LIB=ON -DBUILD_PLUGIN=ON ${{ matrix.toolset_option }} ..
         cmake --build . -j 4
     - name: Run tests
       working-directory: build
@@ -66,7 +66,7 @@ jobs:
     - name: Compile tests
       working-directory: build
       run: |
-        cmake -DBUILD_TESTING=ON -DBUILD_LIB=ON ..
+        cmake -DBUILD_TESTING=ON -DBUILD_LIB=ON -DBUILD_PLUGIN=ON ..
         make -j4
     - name: Run tests
       working-directory: build