update docs

Author: Oren Novotny

docs/more-info/variables.md

@@ -10,6 +10,7 @@ For the `release/3.0.0` branch of GitVersion it shows:
   "PreReleaseTag":"beta.1",
   "PreReleaseTagWithDash":"-beta.1",
   "BuildMetaData":1,
+  "BuildMetaDataPadded": "0001",
   "FullBuildMetaData":"1.Branch.release/3.0.0.Sha.28c853159a46b5a87e6cc9c4f6e940c59d6bc68a",
   "MajorMinorPatch":"3.0.0",
   "SemVer":"3.0.0-beta.1",