Update pyqtgraph requirement from ~=0.11.0 to ~=0.11.1

Updates the requirements on [pyqtgraph](https://github.com/pyqtgraph/pyqtgraph) to permit the latest version.
- [Release notes](https://github.com/pyqtgraph/pyqtgraph/releases)
- [Changelog](https://github.com/pyqtgraph/pyqtgraph/blob/master/CHANGELOG)
- [Commits](pyqtgraph/pyqtgraph@pyqtgraph-0.11.0...pyqtgraph-0.11.1)

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -90,5 +90,5 @@ wrapt~=1.12.1
 zipp~=3.4.0
 # not strict requirements but needed for the legacy pyqtgraph based plotting
 PyQt5<5.13 # 5.12 is the last version that spyder supports at the moment
-pyqtgraph~=0.11.0
+pyqtgraph~=0.11.1
 QtPy==1.9.0