CI: adding oldest dependencies check to matrix, and more devdeps dependencies, too

Author: bsipocz

tox.ini

@@ -15,17 +15,20 @@ deps =
     -rsite/requirements.txt
     -rrequirements.txt
 
-    # TODO: add the oldest supported versions of all the dependencies here
-    # oldestdeps: numpy==1.18
-    # oldestdeps: matplotlib==3.1.2
-    # oldestdeps: scipy==1.4
+    oldestdeps: numpy==1.20
+    oldestdeps: matplotlib==3.4
+    oldestdeps: scipy==1.6
+    oldestdeps: pandas==1.2
+    oldestdeps: statsmodels==0.13
 
 allowlist_externals = bash
 
 commands =
     devdeps: pip install -U --pre --only-binary :all: -i https://pypi.anaconda.org/scipy-wheels-nightly/simple numpy
     devdeps: pip install -U --pre --only-binary :all: -i https://pypi.anaconda.org/scipy-wheels-nightly/simple scipy
     devdeps: pip install -U --pre --only-binary :all: -i https://pypi.anaconda.org/scipy-wheels-nightly/simple matplotlib
+    devdeps: pip install -U --pre --only-binary :all: -i https://pypi.anaconda.org/scipy-wheels-nightly/simple pandas
+    devdeps: pip install -U --pre --only-binary :all: -i https://pypi.anaconda.org/scipy-wheels-nightly/simple statsmodels
 
     pip freeze