Handle newlines in release notes test (elastic#130134) (elastic#130352)

Newlines are system dependent. The release notes generator uses groovy's
template engine, which produces system dependent newlines. This commit
adjusts the test to account for newlines on both windows and nix
systems.

Author: rjernst

build-tools-internal/src/test/java/org/elasticsearch/gradle/internal/release/ReleaseNotesGeneratorTest.java

@@ -20,7 +20,7 @@
 import java.util.Objects;
 import java.util.Set;
 
-import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.arrayContaining;
 import static org.junit.Assert.assertThat;
 
 public class ReleaseNotesGeneratorTest {
@@ -42,7 +42,10 @@ public void generateFile_rendersCorrectMarkup() throws Exception {
         final String actualOutput = ReleaseNotesGenerator.generateFile(template, QualifiedVersion.of("8.2.0-SNAPSHOT"), entries);
 
         // then:
-        assertThat(actualOutput, equalTo(expectedOutput));
+        String[] expectedLines = expectedOutput.replace("\r", "").split("\n");
+        String[] actualLines = actualOutput.split("\n");
+
+        assertThat(actualLines, arrayContaining(expectedLines));
     }
 
     private Set<ChangelogEntry> getEntries() {