README.md in opentelemetry-instrumentation-net_http-0.12.0 vs README.md in opentelemetry-instrumentation-net_http-0.13.0

@@ -30,11 +30,11 @@
 end
 ```
 
 ## Example
 
-An example of usage can be seen in [`example/net_http.rb`](https://github.com/open-telemetry/opentelemetry-ruby/blob/master/instrumentation/net_http/example/net_http.rb).
+An example of usage can be seen in [`example/net_http.rb`](https://github.com/open-telemetry/opentelemetry-ruby/blob/main/instrumentation/net_http/example/net_http.rb).
 
 ## How can I get involved?
 
 The `opentelemetry-instrumentation-net_http` gem source is [on github][repo-github], along with related gems including `opentelemetry-api` and `opentelemetry-sdk`.
 
@@ -45,9 +45,9 @@
 Apache 2.0 license. See [LICENSE][license-github] for more information.
 
 [net-http-home]: https://docs.ruby-lang.org/en/2.0.0/Net/HTTP.html
 [bundler-home]: https://bundler.io
 [repo-github]: https://github.com/open-telemetry/opentelemetry-ruby
-[license-github]: https://github.com/open-telemetry/opentelemetry-ruby/blob/master/LICENSE
+[license-github]: https://github.com/open-telemetry/opentelemetry-ruby/blob/main/LICENSE
 [ruby-sig]: https://github.com/open-telemetry/community#ruby-sig
 [community-meetings]: https://github.com/open-telemetry/community#community-meetings
 [ruby-gitter]: https://gitter.im/open-telemetry/opentelemetry-ruby