Drop support for numpy<1.21

Author: eerovaher

.github/workflows/ci_workflows.yml

@@ -28,14 +28,6 @@ jobs:
             toxenv: test-oldestdeps
             toxargs: -v
 
-          - name: Test with medium old supported versions of our dependencies
-            # Test that we do not have a problem with some specific version (gh-101).
-            # Comment out if not needed.
-            os: ubuntu-22.04
-            python: 3.9
-            toxenv: test-olddeps
-            toxargs: -v
-
           - name: Test with development versions of our dependencies
             os: ubuntu-latest
             python: '3.14'

pyproject.toml

@@ -26,7 +26,7 @@ classifiers = [
 ]
 urls = {Homepage = "https://github.com/liberfa/pyerfa"}
 requires-python = ">=3.9"
-dependencies = ["numpy>=1.19.3"]
+dependencies = ["numpy>=1.21"]
 dynamic = ["version"]
 
 [project.optional-dependencies]

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    test{,-oldestdeps,-olddeps,-devdeps}
+    test{,-oldestdeps,-devdeps}
     build_docs
     linkcheck
     codestyle
@@ -32,13 +32,11 @@ changedir = .tmp/{envname}
 description =
     run tests
     devdeps: with the latest developer version of key dependencies
-    olddeps: with medium old versions of key dependencies
     oldestdeps: with the oldest supported version of key dependencies
 
 # The following provides some specific pinnings for key packages
 deps =
-    oldestdeps: numpy==1.19.*  # astropy LTS
-    olddeps: numpy==1.20.*  # something potentially problematic (see gh-101)
+    oldestdeps: numpy==1.21.*
     devdeps: numpy>=0.0.dev0
 
 # The following indicates which extras_require from setup.cfg will be installed