More licensing format updates

LICENSE.txt

@@ -1,9 +1,3 @@
-Constellix Certbot DNS Plugin
-Copyright 2020 Constellix, a division of Tiggee LLC.
-Licensed Apache Version 2.0
-
-Text of Apache License
-======================
                                  Apache License
                            Version 2.0, January 2004
                         http://www.apache.org/licenses/
@@ -178,16 +172,3 @@ Text of Apache License
       defend, and hold each Contributor harmless for any liability
       incurred by, or claims asserted against, such Contributor by reason
       of your accepting any such warranty or additional liability.
-
-   END OF TERMS AND CONDITIONS
-
-   APPENDIX: How to apply the Apache License to your work.
-
-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
-      identification within third-party archives.

README.md

@@ -98,3 +98,16 @@ The extra `certbot-dns-constellix:` is required due to how older versions of Cer
 
 For more options please check the certbot documentation.
 
+## License
+
+Copyright 2020 Constellix, a division of Tiggee 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.