Set version to '1.5.1-preview.{height}'

source/version.json

@@ -1,6 +1,6 @@
 {
   "$schema": "https://raw.githubusercontent.com/dotnet/Nerdbank.GitVersioning/master/src/NerdBank.GitVersioning/version.schema.json",
-  "version": "1.5.0-preview.{height}",
+  "version": "1.5.1-preview.{height}",
   "assemblyVersion": {
     "precision": "revision"
   },
@@ -18,7 +18,7 @@
   },
   "release": {
     "branchName": "release-v{version}",
-    "firstUnstableTag": "preview",
-    "versionIncrement": "build"
+    "versionIncrement": "build",
+    "firstUnstableTag": "preview"
   }
 }