ensure pour mojo handles winegrower-core presence too (#6)

diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index 3aa4750..9d59ab7 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -31,7 +31,7 @@
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '1.8', '11.0.4' ]
+        java: [ '11.0.4' ]
     steps:
     - name: Clone
       uses: actions/checkout@v1
@@ -62,7 +62,7 @@
     - name: Set up JDK
       uses: actions/setup-java@v1
       with:
-        java-version: '1.8'
+        java-version: '11.0.4'
     - name: Build
       run: mvn install -DskipTests ossindex:audit
     - name: Remove Snapshots Before Caching
diff --git a/winegrower-extension/winegrower-build/winegrower-maven-plugin/src/main/java/org/apache/winegrower/extension/build/maven/PourMojo.java b/winegrower-extension/winegrower-build/winegrower-maven-plugin/src/main/java/org/apache/winegrower/extension/build/maven/PourMojo.java
index c79be06..ecc0a3b 100644
--- a/winegrower-extension/winegrower-build/winegrower-maven-plugin/src/main/java/org/apache/winegrower/extension/build/maven/PourMojo.java
+++ b/winegrower-extension/winegrower-build/winegrower-maven-plugin/src/main/java/org/apache/winegrower/extension/build/maven/PourMojo.java
@@ -127,9 +127,11 @@
                 throw new IllegalArgumentException(e);
             }
         }).collect(toList());
-        final boolean excludeParentClasses = jars.stream()
+        final boolean excludeOsgi = jars.stream()
              .anyMatch(it -> it.getName().startsWith("org.osgi.") || it.getName().startsWith("osgi."));
-        if (excludeParentClasses) {
+        final boolean hasWinegrower = jars.stream()
+             .anyMatch(it -> it.getName().startsWith("winegrower-core"));
+        if (excludeOsgi) {
             // add build-common
             final File buildCommon = Files.toFile(parent.getResource("org/apache/winegrower/extension/build/common/Run.class"));
             try {
@@ -140,15 +142,14 @@
         }
         return urls.isEmpty() ? parent : new URLClassLoader(
                 urls.toArray(new URL[0]),
-                !excludeParentClasses ? parent : new ClassLoader(parent) {
+                !excludeOsgi || !hasWinegrower ? parent : new ClassLoader(parent) {
                     @Override
                     protected Class<?> loadClass(final String name, final boolean resolve) throws ClassNotFoundException {
                         if (name.startsWith("org.")) {
                             final String sub = name.substring("org.".length());
                             if (sub.startsWith("osgi.")) {
                                 throw new ClassNotFoundException(name);
-                            }
-                            if (sub.startsWith("apache.")) {
+                            } else if (sub.startsWith("apache.")) {
                                 final String apache = sub.substring("apache.".length());
                                 if (apache.startsWith("winegrower.")) {
                                     throw new ClassNotFoundException(name);