docs: extend upgrade instructions (#1249)

This adds the pip / pipx commands to upgrade all the dependencies. This makes directed actions like #1225 (comment) unnecessary.

README.md

@@ -133,12 +133,20 @@ Upgrading
 
 ### If installed using pipx
 
-` pipx upgrade yewtube `
+`pipx upgrade yewtube`
+
+Optionally with upgrading all dependencies:
+
+`pipx runpip yewtube install --upgrade-strategy eager --upgrade yewtube`
 
 ### If installed using pip
 
 `pip install --upgrade yewtube`
 
+Optionally with upgrading all dependencies:
+
+`pip install --upgrade-strategy eager --upgrade yewtube`
+
 Usage
 -----