refactor(GitVersion.Core): add const var DefaultLabelNumberPattern

Author: BinToss

src/GitVersion.Core/Configuration/BranchConfiguration.cs

@@ -24,7 +24,7 @@ internal record BranchConfiguration : IBranchConfiguration
 
     [JsonPropertyName("label-number-pattern")]
     [JsonPropertyDescription(@"The regular expression pattern to use to extract the number from the branch name. Defaults to '[/-](?<number>\d+)[-/]'.")]
-    [JsonPropertyDefault(@"[/-](?<number>\d+)[-/]")]
+    [JsonPropertyDefault(ConfigurationConstants.DefaultLabelNumberPattern)]
     public string? LabelNumberPattern { get; internal set; }
 
     [JsonPropertyName("track-merge-target")]

src/GitVersion.Core/Configuration/ConfigurationConstants.cs

@@ -21,6 +21,7 @@ internal static class ConfigurationConstants
     internal const string StringDefaultUpdateBuildNumber = "true";
     public const SemanticVersionFormat DefaultSemanticVersionFormat = SemanticVersionFormat.Strict;
     internal const string StringDefaultSemanticVersionFormat = nameof(SemanticVersionFormat.Strict);
+    public const string DefaultLabelNumberPattern = @"[/-](?<number>\d+)[-/]";
 
     public const string MainBranchKey = "main";
     public const string MasterBranchKey = "master";