Devops: fix the nightly build

The nightly build against the `develop` branch of `aiida-core` was
failing at the installation of the Python dependencies when running
against Python 3.7. The reason is that the current `develop` branch has
dropped support for Python 3.7 and the `pip` is then failing to install
a version of `pymatgen` that matches the dependency requirements. The
solution is simply to not run against Python 3.7 anymore.

Furthermore, the workflow is updated to match the exact same setup
procedure as the `ci.yml` workflow which has also recently been updated.
The workflow is also renamed to `develop` as that is the name of the
file itself and is a bit more concrete than nightly build, since you can
have many nightly builds of different kinds in principle, but this one
is especially used to test against `aiida-core`'s `develop` branch.

.github/workflows/develop.yml

@@ -1,4 +1,4 @@
-name: Nightly Build
+name: develop
 
 on:
  schedule:
@@ -9,22 +9,15 @@ jobs:
  tests:
 
  if: github.repository == 'aiidateam/aiida-quantumespresso' # Prevent running the builds on forks as well
-
  runs-on: ubuntu-latest
 
  strategy:
  matrix:
- python-version: [3.7, 3.8, 3.9]
+ python-version: ['3.8', '3.9']
 
  services:
  postgres:
- image: postgres:10
- env:
- POSTGRES_DB: test_${{ matrix.backend }}
- POSTGRES_PASSWORD: ''
- POSTGRES_HOST_AUTH_METHOD: trust
- ports:
- - 5432:5432
+ image: postgres:12
  rabbitmq:
  image: rabbitmq:latest
  ports:
@@ -33,8 +26,7 @@ jobs:
  steps:
  - uses: actions/checkout@v2
 
- - name: Cache python dependencies
- id: cache-pip
+ - name: Cache Python dependencies
  uses: actions/cache@v1
  with:
  path: ~/.cache/pip
@@ -47,25 +39,18 @@ jobs:
  with:
  python-version: ${{ matrix.python-version }}
 
- - name: Install system dependencies
- run: |
- sudo apt update
- sudo apt install postgresql-12
-
- - name: Install python dependencies
+ - name: Install Python dependencies
  continue-on-error: true
  id: install
  run: |
- pip install --upgrade setuptools
+ pip install --upgrade pip setuptools wheel
  pip install git+https://github.com/aiidateam/aiida-core@develop#egg=aiida-core[atomic_tools]
  pip install -e .[tests]
- reentry scan
 
  - name: Run pytest
  continue-on-error: true
  id: tests
- run:
- pytest -sv tests
+ run: pytest -sv tests
 
  - name: Slack notification
  if: steps.install.outcome == 'Failure' || steps.tests.outcome == 'Failure'