update remix-plugin to last version

package.json

@@ -43,7 +43,6 @@
     "remix-analyzer": "0.3.1",
     "remix-debug": "0.3.1",
     "remix-lib": "0.4.1",
-    "remix-plugin": "latest",
     "remix-solidity": "0.3.1",
     "remix-tabs": "^1.0.0",
     "remix-tests": "0.1.1",
@@ -65,6 +64,7 @@
   },
   "dependencies": {
     "http-server": "0.9.0",
+    "remix-plugin": "0.0.1-alpha.19",
     "remixd": "0.1.8-alpha.6"
   },
   "repository": {