Update tox config

tox.ini

@@ -1,22 +1,16 @@
 [tox]
 envlist = 
-    ; qt 5.12.x
-    py{27,37}-pyside2-pip
-    py{35,37}-pyqt5-pip
+    ; qt latest
+    py{37,38}-{pyqt5,pyside2}_latest
 
-    ; qt 5.9.7
-    py{27,37}-pyqt5-conda
-    py{27,37}-pyside2-conda
+    ; qt 5.12.x (LTS) 
+    py{36,37}-{pyqt5,pyside2}_512
 
-    ; qt 5.6.2
-    py35-pyqt5-conda
-    ; consider dropping support...
-    ; py35-pyside2-conda
+    ; qt 5.9.7 (LTS)
+    py36-{pyqt5,pyside2}_59_conda
 
     ; qt 4.8.7
-    py{27,36}-pyqt4-conda
-    py{27,36}-pyside-conda
-
+    py27-{pyqt4,pyside}_conda
 
 [base]
 deps =
@@ -34,17 +28,22 @@ deps=
     {[base]deps}
     pytest-cov
     pytest-xdist
-    pyside2-pip: pyside2
-    pyqt5-pip: pyqt5
+    h5py
+    pyside2_512: pyside2>=5.12,<5.13
+    pyqt5_512: pyqt5>=5.12,<5.13
+    pyside2_latest: pyside2
+    pyqt5_latest: pyqt5
 
 conda_deps=
-    pyside2-conda: pyside2
-    pyside-conda: pyside
-    pyqt5-conda: pyqt
-    pyqt4-conda: pyqt=4
-    
+    pyside2_59_conda: pyside2=5.9
+    pyqt5_59_conda: pyqt=5.9
+    pyqt4_conda: pyqt=4
+    pyside_conda: pyside
+
 conda_channels=
     conda-forge
+    free
+
 commands=
     python -c "import pyqtgraph as pg; pg.systemInfo()"
     pytest {posargs:.}