fix(deps): update dependency ejs to v3 (#774)

Co-authored-by: renovate[bot] <renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

packages/opencensus-core/package-lock.json

@@ -51,7 +51,7 @@
   },
   "devDependencies": {
     "@opencensus/nodejs": "^0.0.20",
-    "@types/ejs": "^2.6.0",
+    "@types/ejs": "^3.0.0",
     "@types/express": "^4.11.1",
     "@types/extend": "^3.0.0",
     "@types/mocha": "^7.0.0",
@@ -68,7 +68,7 @@
   },
   "dependencies": {
     "@opencensus/core": "^0.0.20",
-    "ejs": "^2.5.8",
+    "ejs": "^3.0.0",
     "express": "^4.16.3"
   }
 }