feat(project): drop support for Python 3.7 (#618)

3.7 has been EOL for over a year and accounts for
a small number of downloads

Author: stainless-app[bot]

README.md

@@ -2,7 +2,7 @@
 
 [![PyPI version](https://img.shields.io/pypi/v/lithic.svg)](https://pypi.org/project/lithic/)
 
-The Lithic Python library provides convenient access to the Lithic REST API from any Python 3.7+
+The Lithic Python library provides convenient access to the Lithic REST API from any Python 3.8+
 application. The library includes type definitions for all request params and response fields,
 and offers both synchronous and asynchronous clients powered by [httpx](https://github.com/encode/httpx).
 
@@ -452,7 +452,7 @@ print(lithic.__version__)
 
 ## Requirements
 
-Python 3.7 or higher.
+Python 3.8 or higher.
 
 ## Contributing
 

pyproject.toml

@@ -16,11 +16,10 @@ dependencies = [
     "sniffio",
     "cached-property; python_version < '3.8'",
 ]
-requires-python = ">= 3.7"
+requires-python = ">= 3.8"
 classifiers = [
   "Typing :: Typed",
   "Intended Audience :: Developers",
-  "Programming Language :: Python :: 3.7",
   "Programming Language :: Python :: 3.8",
   "Programming Language :: Python :: 3.9",
   "Programming Language :: Python :: 3.10",
@@ -139,7 +138,7 @@ filterwarnings = [
 # there are a couple of flags that are still disabled by
 # default in strict mode as they are experimental and niche.
 typeCheckingMode = "strict"
-pythonVersion = "3.7"
+pythonVersion = "3.8"
 
 exclude = [
     "_dev",