Allow branch names starting with master

src/GitVersionCore.Tests/ConfigProviderTests.CanWriteOutEffectiveConfiguration.approved.txt

@@ -29,7 +29,7 @@ branches:
     increment: Patch
     prevent-increment-of-merged-branch-version: true
     track-merge-target: false
-    regex: master
+    regex: master$
     source-branches:
     - develop
     - release

src/GitVersionCore.Tests/IntegrationTests/OtherScenarios.cs

@@ -46,6 +46,20 @@ public void AllowNotHavingMaster()
             }
         }
 
+        [Test]
+        public void AllowHavingVariantsStartingWithMaster()
+        {
+            using (var fixture = new EmptyRepositoryFixture())
+            {
+                fixture.Repository.MakeACommit();
+                fixture.Repository.MakeATaggedCommit("1.0.0");
+                fixture.Repository.MakeACommit();
+                Commands.Checkout(fixture.Repository, fixture.Repository.CreateBranch("masterfix"));
+
+                fixture.AssertFullSemver("1.0.1-masterfix.1+1");
+            }
+        }
+
         [Test]
         public void AllowHavingMainInsteadOfMaster()
         {

src/GitVersionCore/Configuration/ConfigurationProvider.cs

@@ -21,7 +21,7 @@ public class ConfigurationProvider
         public const string HotfixBranchRegex = "hotfix(es)?[/-]";
         public const string SupportBranchRegex = "support[/-]";
         public const string DevelopBranchRegex = "dev(elop)?(ment)?$";
-        public const string MasterBranchRegex = "master";
+        public const string MasterBranchRegex = "master$";
         public const string MasterBranchKey = "master";
         public const string ReleaseBranchKey = "release";
         public const string FeatureBranchKey = "feature";