Drop support for EOL Python 3.7

Author: hugovk

Diff for: doc/installation.rst

@@ -25,7 +25,7 @@ GitHub. It also hosts the `issue tracker`_.
 Dependencies
 ------------
 
-Python-RSA is compatible with Python versions 3.7 and newer. The last
+Python-RSA is compatible with Python versions 3.8 and newer. The last
 version with Python 2.7 support was Python-RSA 4.0.
 
 Python-RSA has very few dependencies. As a matter of fact, to use it

Diff for: pyproject.toml

@@ -16,7 +16,6 @@ classifiers = [
   "Operating System :: OS Independent",
   "Programming Language :: Python",
   "Programming Language :: Python :: 3",
-  "Programming Language :: Python :: 3.7",
   "Programming Language :: Python :: 3.8",
   "Programming Language :: Python :: 3.9",
   "Programming Language :: Python :: 3.10",