Remove disclaimer in README (#1590)

* remove disclaimer; move feedback request to about section
* remove redundant mention of forum
* add semantic versioning to maintenance.md

Co-authored-by: Wei Ji <[email protected]>

Author: willschlitzer

README.rst

@@ -50,22 +50,6 @@ or visit the `PyGMT Gallery <https://www.pygmt.org/latest/gallery>`__.
     :align: center
     :target: https://www.youtube.com/watch?v=SSIGJEe0BIk
 
-
-Disclaimer
-----------
-
-🚨 **This package is still undergoing rapid development.** 🚨
-
-All of the API (functions/classes/interfaces) is subject to change until we reach v1.0.0
-as per the `semantic versioning specification <https://semver.org/spec/v2.0.0.html>`__.
-There may be non-backward compatible changes as we experiment with new design ideas and
-implement new features. **This is not a finished product, use with caution.**
-
-We welcome any feedback and ideas!
-Let us know by submitting
-`issues on GitHub <https://github.com/GenericMappingTools/pygmt/issues>`__
-or by posting on our `Discourse forum <https://forum.generic-mapping-tools.org>`__.
-
 About
 -----
 
@@ -78,7 +62,6 @@ We rely heavily on new features that have been implemented in GMT 6.0. In partic
 a new *modern execution mode* that greatly simplifies figure creation. **These features
 are not available in the 5.4 version of GMT**.
 
-
 Project goals
 -------------
 

doc/maintenance.md

@@ -177,8 +177,8 @@ adjusted upward on every major and minor release, but never on a patch release.
 ## Backwards compatibility and deprecation policy
 
 PyGMT is still undergoing rapid development. All of the API is subject to change
-until the v1.0.0 release.
-
+until the v1.0.0 release. Versioning in PyGMT is based on the
+[semantic versioning specification](https://semver.org/spec/v2.0.0.html) (e.g. vMAJOR.MINOR.PATCH).
 Basic policy for backwards compatibility:
 
 - Any incompatible changes should go through the deprecation process below.