feat: add mcbuild plugin

res/schemas/beet_pipeline.json

@@ -109,6 +109,10 @@
             "const": "beet.contrib.lantern_load",
             "description": "Adds Lantern Load runtime dependencies"
           },
+          {
+            "const": "beet.contrib.mcbuild",
+            "description": "Builds a MC-Build project"
+          },
           {
             "const": "beet.contrib.minify_function",
             "description": "Minifies function files"
@@ -206,6 +210,10 @@
           "description": "lantern_load plugin settings",
           "$ref": "contrib/lantern_load.json"
         },
+        "mcbuild": {
+          "description": "mcbuild plugin settings",
+          "$ref": "contrib/mcbuild.json"
+        },
         "render": {
           "description": "render plugin settings",
           "$ref": "contrib/render.json"

res/schemas/contrib/mcbuild.json

@@ -0,0 +1,14 @@
+{
+	"$schema": "https://json-schema.org/draft/2020-12/schema",
+	"type": "object",
+	"properties": {
+		"source": {
+			"type": "string",
+			"description": "The source directory of the project. Defaults to './mcbuild'"
+		},
+		"force_rebuild": {
+			"type": "boolean",
+			"description": "Force the plugin to re-run MC-Build when beet updates the project, even if the source has not been changed."
+		}
+	}
+}