Unpin imageio and add warningfilter

TODO.txt

@@ -36,3 +36,6 @@ Other (2022)
 ------------
 * Remove custom code for ignored warning in `skimage/_shared/testing.py` relating
   to (sparse) matricies (instead of arrays).
+* Remove warningsfilter for imageio and Pillow once
+  https://github.com/python-pillow/Pillow/pull/7125 is shipped in the minimal required
+  version of pillow (probably the release after Pillow 9.5.0).

pyproject.toml

@@ -39,7 +39,7 @@ dependencies = [
     'scipy>=1.8',
     'networkx>=2.8',
     'pillow>=9.0.1',
-    'imageio>=2.27,<2.31',
+    'imageio>=2.27',
     'tifffile>=2022.8.12',
     'PyWavelets>=1.1.1',
     'packaging>=21',
@@ -72,7 +72,7 @@ default = [
     'scipy>=1.8',
     'networkx>=2.8',
     'pillow>=9.0.1',
-    'imageio>=2.27,<2.31',
+    'imageio>=2.27',
     'tifffile>=2022.8.12',
     'PyWavelets>=1.1.1',
     'packaging>=21',

requirements/default.txt

@@ -2,7 +2,7 @@ numpy>=1.21.1
 scipy>=1.8
 networkx>=2.8
 pillow>=9.0.1
-imageio>=2.27,<2.31
+imageio>=2.27
 tifffile>=2022.8.12
 PyWavelets>=1.1.1
 packaging>=21

skimage/_shared/testing.py

@@ -267,6 +267,19 @@ def setup_test():
             category=DeprecationWarning
         )
 
+        # Temporary warning raised by imageio about change in Pillow. May be removed
+        # once https://github.com/python-pillow/Pillow/pull/7125 is shipped in the
+        # minimal required version of pillow (probably the release after Pillow 9.5.0)
+        warnings.filterwarnings(
+            "default",
+            message=(
+                "Loading 16-bit (uint16) PNG as int32 due to limitations in pillow's "
+                "PNG decoder. This will be fixed in a future version of pillow which "
+                "will make this warning dissapear."
+            ),
+            category=UserWarning,
+        )
+
 
 def teardown_test():
     """Default package level teardown routine for skimage tests.