clearly indicate python2 is dying

CHANGELOG.md

@@ -4,11 +4,11 @@ Version numbers follow [semantic versioning](https://semver.org)
 
 ## phonemizer-2.0
 
-* **incompatible change:** starting with *phonemizer-2.0* only python3 is
-  supported. Compatibility with python2 is no more ensured nor tested.
+* **incompatible change:** starting with ``phonemizer-2.0`` only python3 is
+  supported. **Compatibility with python2 is no more ensured nor tested.**
   https://pythonclock.org.
 
-* **bugfix** **new ``--language-switch`` option to use with ``espeak`` backend
+* **bugfix** new ``--language-switch`` option to use with ``espeak`` backend
   to deals with language switching on phonemized output. In previous version
   there was a bug in detection of the language switching flags (sometimes
   removed, sometimes not). Now you can choose to keep the flags, to remove them,

README.md

@@ -35,6 +35,10 @@ https://doi.org/10.5281/zenodo.1045825)
 
 ## Installation
 
+* **You need python3.** If you really need to use python2, use an [older
+  version](https://github.com/bootphon/phonemizer/releases/tag/v1.1) of
+  phonemizer.
+
 * First you need to install festival and espeak-ng on your system. Visit
   [this festival link](http://www.festvox.org/docs/manual-2.4.0/festival_6.html#Installation)
   and [that espeak-ng one](https://github.com/espeak-ng/espeak-ng#espeak-ng-text-to-speech)