Enable nightly toolchain CI

Author: czechboy0

.github/workflows/pull_request.yml

@@ -21,15 +21,14 @@ jobs:
             linux_5_10_arguments_override: "--explicit-target-dependency-import-check error"
             linux_6_0_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error"
             linux_nightly_6_0_arguments_override: "--explicit-target-dependency-import-check error"
-            linux_nightly_main_enabled: false
+            linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error"
 
     integration-test:
         name: Integration test
         uses: apple/swift-nio/.github/workflows/swift_matrix.yml@main
         with:
             name: "Integration test"
             matrix_linux_command: "apt-get update -yq && apt-get install -yq jq && SWIFT_OPENAPI_GENERATOR_REPO_URL=file://${GITHUB_WORKSPACE} ./scripts/run-integration-test.sh"
-            matrix_linux_nightly_main_enabled: false
 
     compatibility-test:
       name: Compatibility test
@@ -56,4 +55,3 @@ jobs:
         with:
             name: "Example packages"
             matrix_linux_command: "./scripts/test-examples.sh"
-            matrix_linux_nightly_main_enabled: false