Change to Apache-2.0 licence and add licence file to repository

LICENCE

@@ -0,0 +1,12 @@
+Copyright (c) Octopus Deploy and contributors. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+these files 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

@@ -23,7 +23,7 @@
     "octopus"
   ],
   "author": "Octopus Deploy",
-  "license": "ISC",
+  "license": "Apache-2.0",
   "bugs": {
     "url": "https://github.com/OctopusDeploy/login/issues"
   },