Add astropy version info to known install issues
@@ -39,7 +39,8 @@ If your issue is not adressed, please send an email to the mailing list.
Known issues
------------
-- **Astropy =<3.1 and Matplotlib 3.0**: There is an incompatibility between
+- **Astropy <3.0.5 and Matplotlib 3.0**: There is an incompatibility between
WCSAxes and Matplotlib 3.0, which causes the inline plotting in notebooks to
fail. The issue as well as a temporary workaround is decribed
`here https://github.com/gammapy/gammapy/issues/1843#issuecomment-435909533`_.
+The issue has been fixed since Astropy 3.0.5.
