Problem with Trend sensor (stopped working)

I had been using the Trend sensor successfully for a while but it has now broken (possibly when updating to 0.82) with the following in the log file:

2018-11-17 16:39:21 ERROR (Thread-11) [homeassistant.util.package] Unable to install package numpy==1.15.3: Failed building wheel for numpy
Failed cleaning build dir for numpy
locationsharinglib 1.2.1 has requirement requests==2.18.4, but you'll have requests 2.20.0 which is incompatible.
Command "/srv/homeassistant/bin/python3 -u -c "import setuptools, tokenize;__file__='/tmp/pip-install-srjsysos/numpy/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /tmp/pip-record-l1dvrdld/install-record.txt --single-version-externally-managed --compile --install-headers /srv/homeassistant/include/site/python3.5/numpy" failed with error code 1 in /tmp/pip-install-srjsysos/numpy/
You are using pip version 10.0.1, however version 18.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
2018-11-17 16:39:21 ERROR (MainThread) [homeassistant.requirements] Not initializing binary_sensor.trend because could not install requirement numpy==1.15.3

This was a manual installation on a Raspberry Pi 2 in a Python virtual environment. Any suggestions on how I can get this working again?

Edit: I’ve been able to get it working again by manually installing numpy version 1.15.3 using the command pip3 install numpy==1.15.3 from the virtual environment, but I don’t understand why Home Assistant failed to do this.

Just had the same happen again when updating to 0.83 with numpy 1.15.4. It looks like Home Assistant isn’t able to update numpy automatically and needs a manual pip3 install --upgrade numpy or pip3 install numpy==version to fix it.