MAINT: Discontinue Python 3.7 support

Official end of security fixes in June 2023
https://peps.python.org/pep-0537/

.travis.yml

@@ -3,9 +3,10 @@ if: branch = master
 
 language: python
 python:
-    - "3.7"
     - "3.8"
     - "3.9"
+    - "3.10"
+    - "3.11"
 
 sudo: false
 dist: xenial

setup.cfg

@@ -32,10 +32,10 @@ classifiers =
     Natural Language :: English
     Operating System :: OS Independent
     Programming Language :: Python :: 3 :: Only
-    Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
+    Programming Language :: Python :: 3.11
     Topic :: Scientific/Engineering :: GIS
     Topic :: Scientific/Engineering :: Information Analysis
     Topic :: Scientific/Engineering :: Mathematics
@@ -46,8 +46,7 @@ install_requires =
     numpy >= 1.20
     scipy >= 1.5
     python-igraph >= 0.9
-    importlib-metadata >= 1.0 ; python_version < "3.8"
-python_requires = >=3.7
+python_requires = >=3.8
 packages = find:
 package_dir =
     = src

src/pyunicorn/version.py

@@ -12,11 +12,6 @@
 # and J. Kurths, "Unified functional network and nonlinear time series analysis
 # for complex systems science: The pyunicorn package"
 
-import sys
-
-if sys.version_info >= (3, 8):
-    from importlib import metadata
-else:
-    import importlib_metadata as metadata
+from importlib import metadata
 
 __version__ = metadata.version('pyunicorn')