Add minVersion to template mixin config (#41)

* Add minVersion to mixin config

* Bump loader dep requriement to >=0.7.4

src/main/resources/fabric.mod.json

@@ -27,7 +27,7 @@
   ],
 
   "depends": {
-    "fabricloader": ">=0.7.2",
+    "fabricloader": ">=0.7.4",
     "fabric": "*",
     "minecraft": "1.15.x"
   },

src/main/resources/modid.mixins.json

 {
   "required": true,
+  "minVersion": "0.8",
   "package": "net.fabricmc.example.mixin",
   "compatibilityLevel": "JAVA_8",
   "mixins": [