bump some testing requirements (#2736)

* bump some testing requirements
+ matplotlib >=3.6.0
+ dython ~=0.7.6

(cherry picked from commit 708f11d)

requirements/classification_test.txt

@@ -1,7 +1,7 @@
 # NOTE: the upper bound for the package version is only set for CI stability, and it is dropped while installing this package
 #  in case you want to preserve/enforce restrictions on the latest compatible version, add "strict" as an in-line comment
 
-pandas >=1.4.0, <=2.2.2
+pandas >1.4.0, <=2.2.2
 netcal >1.0.0, <1.4.0 # calibration_error
 numpy <2.2.0
 fairlearn # group_fairness

requirements/nominal_test.txt

@@ -1,7 +1,7 @@
 # NOTE: the upper bound for the package version is only set for CI stability, and it is dropped while installing this package
 #  in case you want to preserve/enforce restrictions on the latest compatible version, add "strict" as an in-line comment
 
-pandas >1.0.0, <=2.2.2 # cannot pin version due to numpy version incompatibility
-dython <=0.7.7
+pandas >1.4.0, <=2.2.2 # cannot pin version due to numpy version incompatibility
+dython ~=0.7.6
 scipy >1.0.0, <1.15.0 # cannot pin version due to some version conflicts with `oldest` CI configuration
 statsmodels >0.13.5, <0.15.0

requirements/visual.txt

@@ -1,5 +1,5 @@
 # NOTE: the upper bound for the package version is only set for CI stability, and it is dropped while installing this package
 #  in case you want to preserve/enforce restrictions on the latest compatible version, add "strict" as an in-line comment
 
-matplotlib >=3.3.0, <3.10.0
+matplotlib >=3.6.0, <3.10.0
 SciencePlots >= 2.0.0, <2.2.0