Issue GitTools#2148: Limit number of commits traversed

Limit the number of commits traversed when trying to find version from
tags and merge messages to 2 (each).

Solves GitTools#2148

Author: erikbra

src/GitVersionCore/VersionCalculation/BaseVersionCalculators/MergeMessageVersionStrategy.cs

@@ -42,7 +42,9 @@ public virtual IEnumerable<BaseVersion> GetVersions(GitVersionContext context)
                         };
                     }
                     return Enumerable.Empty<BaseVersion>();
-                }).ToList();
+                })
+                .Take(2)
+                .ToList();
             return baseVersions;
         }
 

src/GitVersionCore/VersionCalculation/BaseVersionCalculators/TaggedCommitVersionStrategy.cs

@@ -42,6 +42,7 @@ public IEnumerable<BaseVersion> GetTaggedVersions(GitVersionContext context, Bra
                     return null;
                 })
                 .Where(a => a != null)
+                .Take(2)
                 .ToList();
 
             return tagsOnBranch.Select(t => CreateBaseVersion(context, t));