fix(docs): PIP 21.0+ is required, some minor improvements

README.md

@@ -7,20 +7,28 @@ This is the backend of the Flaschengeist.
 ### Requirements
 - `mysql` or `mariadb`
     - maybe `libmariadb` development files[1]
-- python 3.7+
+- pip 21.0+
 
-[1] By default Flaschengeist uses mysql as database backend, if you are on Windows Flaschengeist uses `PyMySQL`, but on
+*[1] By default Flaschengeist uses mysql as database backend, if you are on Windows Flaschengeist uses `PyMySQL`, but on
 Linux / Mac the faster `mysqlclient` is used, if it is not already installed installing from pypi requires the
-development files for `libmariadb` to be present on your system.
+development files for `libmariadb` to be present on your system.*
 
 ### Install python files
-    pip3 install --user .
+It is recommended to upgrade pip to the latest version before installing:
+
+    python -m pip install --upgrade pip
+
+Default installation with *mariadb*/*mysql* support:
+
+    pip3 install --user ".[mysql]"
+
 or with ldap support
 
     pip3 install --user ".[ldap]"
+
 or if you want to also run the tests:
 
-    pip3 install --user ".[ldap,test]"
+    pip3 install --user ".[ldap,tests]"
 
 You will also need a MySQL driver, recommended drivers are
 - `mysqlclient`