Fix links

Author: ehmicky

.github/ISSUE_TEMPLATE/bug_report.md

@@ -54,4 +54,4 @@ If applicable, add screenshots to help explain your problem.
 Yes/No.
 
 Pull requests are welcome! If you would like to help us fix this bug, please
-check our [contributions guidelines](CONTRIBUTING.md).
+check our [contributions guidelines](../blob/master/CONTRIBUTING.md).

.github/ISSUE_TEMPLATE/feature_request.md

@@ -27,4 +27,4 @@ Example: Another solution would be [...]
 Yes/No.
 
 Pull requests are welcome! If you would like to help us add this feature, please
-check our [contributions guidelines](CONTRIBUTING.md).
+check our [contributions guidelines](../blob/master/CONTRIBUTING.md).

.github/pull_request_template.md

@@ -26,7 +26,7 @@ Example: Another solution would be [...]
 
 Please add a `x` inside each checkbox:
 
-- [ ] I have read the [contribution guidelines](CONTRIBUTING.md)
+- [ ] I have read the [contribution guidelines](../blob/master/CONTRIBUTING.md).
 - [ ] I have added tests (we are enforcing 100% test coverage).
 - [ ] I have added documentation in the `README.md`, the `docs` directory (if
       any) and the `examples` directory (if any).