Исправил регулярку, у нас проект-префиксы с цифрами =)

.semver.txt

@@ -1 +1 @@
-1.0.86
+1.0.87

src/JiraTimeBot/Properties/AssemblyInfo.cs

@@ -26,6 +26,6 @@ using System.Runtime.InteropServices;
 //                                                                             
 // You can specify all the values or you can default the Build and Revision Numbers                                                                             
 // by using the '*' as shown below:                                                                             
-[assembly: AssemblyVersion("1.0.86")] 
-[assembly: AssemblyFileVersion("1.0.86")] 
-[assembly: AssemblyInformationalVersion("1.0.86")] 
+[assembly: AssemblyVersion("1.0.87")] 
+[assembly: AssemblyFileVersion("1.0.87")] 
+[assembly: AssemblyInformationalVersion("1.0.87")] 

src/JiraTimeBot/RepositoryProviders/GitLog.cs

@@ -105,7 +105,7 @@ namespace JiraTimeBot.RepositoryProviders
                         continue;
                     }
 
-                    var regex = new Regex("[a-zA-Z]{1,4}-[0-9]{1,6}");
+                    var regex = new Regex("[a-zA-Z0-9]{1,4}-[0-9]{1,6}");
                     var branch = ListBranchesContaininingCommit(repo, commit.Sha)
                                  .Select(f => f.FriendlyName)
                                  .FirstOrDefault(f => regex.IsMatch(f));