drop support for python 3.7 (#153)

* drop support for python 3.7

* remove python 3.7 from CI

* remove the importlib-metadata requirement

* changelog

* specify the desired python version in the docs

* rename the rtd configuration file to the new official name

Author: keewis

.github/workflows/ci.yml

@@ -40,7 +40,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.7, 3.8, 3.9]
+        python-version: [3.8, 3.9]
 
     steps:
     - name: cancel previous runs

readthedocs.yml renamed to .readthedocs.yaml

@@ -1,7 +1,9 @@
 version: 2
 
 build:
-  image: latest
+  os: ubuntu-20.04
+  tools:
+    python: "3.9"
 
 python:
   install:
@@ -10,4 +12,5 @@ python:
       path: .
 
 sphinx:
+  configuration: docs/conf.py
   fail_on_warning: true

docs/whats-new.rst

@@ -2,6 +2,10 @@
 
 What's new
 ==========
+0.3 (*unreleased*)
+------------------
+- drop support for python 3.7 (:pull:`153`)
+  By `Justus Magin <https://github.com/keewis>`_.
 
 0.2.1 (26 Jul 2021)
 -------------------

setup.cfg

@@ -15,19 +15,17 @@ classifiers =
     License :: OSI Approved :: Apache Software License
     Operating System :: OS Independent
     Programming Language :: Python
-    Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
     Topic :: Scientific/Engineering
 
 [options]
 packages = find:
-python_requires = >=3.7
+python_requires = >=3.8
 install_requires =
     numpy >= 1.17
     xarray >= 0.16.1
     pint >= 0.16
-    importlib-metadata; python_version < "3.8"
 
 [flake8]
 ignore =