update manifest schema for %ProjectVersion% feature

Author: Pathoschild

docs/release-notes.md

@@ -33,6 +33,7 @@
     * The Content Patcher JSON schema now allows decimal values in local tokens (thanks to rikai!).
     * The `$schema` value is no longer validated.
     * Updated Content Patcher schema for Content Patcher 2.7.0.
+    * Updated manifest schema for the new `%ProjectVersion%` value in `Version`.
   * Improved mod compatibility list:
     * Reduced response times with a new cache and client-side fetch.
     * Fixed sort order for mods with non-Latin characters in the name.

src/SMAPI.Web/wwwroot/schemas/manifest.json

@@ -24,8 +24,14 @@
         },
         "Version": {
             "title": "Mod version",
-            "description": "The mod's semantic version. Make sure you update this for each release! SMAPI uses this for update checks, mod dependencies, and compatibility blacklists (if the mod breaks in a future version of the game).",
-            "$ref": "#/definitions/SemanticVersion"
+            "description": "The mod's semantic version, or '%ProjectVersion%' to use the current project's assembly version. Make sure you update this for each release! SMAPI uses this for update checks, mod dependencies, and compatibility blacklists (if the mod breaks in a future version of the game).",
+            "anyOf": [
+                { "$ref": "#/definitions/SemanticVersion" },
+                { "const": "%ProjectVersion%" }
+            ],
+            "@errorMessages": {
+                "anyOf": "Invalid Value. This must be formatted like 1.2.0 or 1.2.0-prerelease.tags (see https://semver.org/ for more info), or the exact string '%ProjectVersion%'."
+            }
         },
         "Description": {
             "title": "Mod description",