Adds check for license header

Signed-off-by: Konstantina Blazhukova <[email protected]>

.eslintrc.js

@@ -29,6 +29,9 @@ module.exports = {
         "plugin:@typescript-eslint/recommended",
         "prettier"
     ],
+    "plugins":  [
+        "header"
+    ],
     "overrides": [
         {
             "env": {
@@ -65,5 +68,31 @@ module.exports = {
             "ignoreMemberSort": false,
             "memberSyntaxSortOrder": ["none", "all", "multiple", "single"],
         }],
+        "header/header": 
+        [
+            'error',
+        'block',
+            [
+                " *",
+                " * Hedera JSON RPC Relay",
+                " *",
+                {"pattern": "* Copyright \(C\) (202[0-9])(-(202[0-9]))?"},
+                "  Hedera Hashgraph, LLC",
+                " *",
+                " * Licensed under the Apache License, Version 2.0 (the \"License\");",
+                " * you may not use this file except in compliance with the License.",
+                " * You may obtain a copy of the License at",
+                " *",
+                " *      http://www.apache.org/licenses/LICENSE-2.0",
+                " *",
+                " * Unless required by applicable law or agreed to in writing, software",
+                " * distributed under the License is distributed on an \"AS IS\" BASIS,",
+                " * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.",
+                " * See the License for the specific language governing permissions and",
+                " * limitations under the License.",
+                " *",
+                " */"
+            ]
+        ]
     },
 };

package.json

@@ -21,6 +21,7 @@
     "eslint-config-airbnb-base": "^15.0.0",
     "eslint-config-prettier": "^8.3.0",
     "eslint-config-standard-with-typescript": "^43.0.1",
+    "eslint-plugin-header": "^3.1.1",
     "eslint-plugin-import": "^2.28.1",
     "eslint-plugin-n": "^15.7.0",
     "ethereum-waffle": "^4.0.7",