doc Python3.8 requirement (#4381)

Author: memsharded

installation.rst

@@ -15,7 +15,7 @@ There are different ways to install Conan:
 Install with pip (recommended)
 ------------------------------
 
-To install latest Conan 2 version using ``pip``, you need a Python >= 3.7
+To install latest Conan 2 version using ``pip``, you need a Python >= 3.8
 distribution installed on your machine. Modern Python distros come with pip pre-installed.
 However, if necessary you can install pip by following the instructions in `pip docs`_.
 
@@ -30,7 +30,7 @@ Install Conan:
 
     **Please READ carefully:**
 
-    - Make sure that your **pip** installation matches your **Python (>= 3.7)** version.
+    - Make sure that your **pip** installation matches your **Python (>= 3.8)** version.
     - On **Linux**, you may need **sudo** permissions to install Conan globally.
     - We strongly recommend using **virtualenvs** (virtualenvwrapper works great) for everything related to Python
       (check https://virtualenvwrapper.readthedocs.io/en/stable/, or https://pypi.org/project/virtualenvwrapper-win/ on Windows).

introduction.rst

@@ -91,7 +91,7 @@ There are some things that are not included in this commitment:
 - Other tools and repositories outside of the Conan client
 
 
-Conan needs Python>=3.7 to run. Conan will deprecate support for Python versions 1 year after those versions have been declared End Of Life (EOL).
+Conan needs Python>=3.8 to run. Conan will deprecate support for Python versions 1 year after those versions have been declared End Of Life (EOL).
 
 If you have any question regarding Conan updates, stability, or any clarification about this definition of stability, please report in the documentation issue tracker: https://github.com/conan-io/docs.