Drop Python 3.7 from the test matrix

Contributes to #270

.appveyor.yml

@@ -1,9 +1,11 @@
+image: Visual Studio 2019
+
 environment:
   matrix:
-    - PYTHON_MAJOR: 3
-      PYTHON_MINOR: 7
     - PYTHON_MAJOR: 3
       PYTHON_MINOR: 8
+    - PYTHON_MAJOR: 3
+      PYTHON_MINOR: 9
 
 cache:
   - .venv -> poetry.lock
@@ -19,8 +21,8 @@ install:
   - set PATH=C:\Python%PYTHON_MAJOR%%PYTHON_MINOR%;%PATH%
   - set PATH=C:\Python%PYTHON_MAJOR%%PYTHON_MINOR%\Scripts;%PATH%
   # Install system dependencies
-  - curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python -
-  - set PATH=%USERPROFILE%\.poetry\bin;%PATH%
+  - curl -sSL https://install.python-poetry.org | python -
+  - set PATH=C:\Users\appveyor\AppData\Roaming\Python\Scripts;%PATH%
   - make doctor
   # Install project dependencies
   - make install

.travis.yml

@@ -2,7 +2,6 @@ dist: focal
 
 language: python
 python:
-  - "3.7"
   - "3.8"
   - "3.9"
   - "3.10.0"

docs/requirements.txt

@@ -1,5 +1,4 @@
 jinja2==3.0.3; python_version >= "3.6"
 markdown==3.3.4; python_version >= "3.6"
 mkdocs==1.3.1; python_version >= "3.6"
-jupyterlab-pygments==0.1.2; python_version >= "3.6"
 pygments==2.10.0; python_version >= "3.5"