Only list the user-specified packages in environment.yml.

Let conda satisfy dependencies on each platform separately.

config/environment.yml

@@ -1,47 +1,12 @@
 name: straw2analysis
 channels:
-  - conda-forge
   - defaults
 dependencies:
-  - appdirs=1.4.4=py_0
-  - attrs=20.3.0=pyhd3eb1b0_0
-  - black=19.3b0=py_0
-  - ca-certificates=2020.12.5=h5b45459_0
-  - certifi=2020.12.5=py39hcbf5309_0
-  - cfgv=3.2.0=py_0
-  - click=7.1.2=py_0
-  - distlib=0.3.1=pyh9f0ad1d_0
-  - editdistance=0.5.3=py39h415ef7b_2
-  - filelock=3.0.12=pyh9f0ad1d_0
-  - flake8=3.8.4=py_0
-  - identify=1.5.10=pyhd3deb0d_0
-  - importlib-metadata=2.0.0=py_1
-  - isort=5.6.4=py_0
-  - mccabe=0.6.1=py39haa95532_1
-  - mypy=0.790=py_0
-  - mypy_extensions=0.4.3=py39hcbf5309_2
-  - nodeenv=1.5.0=pyh9f0ad1d_0
-  - openssl=1.1.1i=h8ffe710_0
-  - pip=20.3.3=py39haa95532_0
-  - pre-commit=2.9.3=py39hcbf5309_0
-  - psutil=5.8.0=py39hb82d6ee_0
-  - pycodestyle=2.6.0=py_0
-  - pyflakes=2.2.0=py_0
-  - python=3.9.1=h6244533_2
-  - python_abi=3.9=1_cp39
-  - pyyaml=5.3.1=py39ha3862ff_1
-  - setuptools=51.0.0=py39haa95532_2
-  - six=1.15.0=pyh9f0ad1d_0
-  - sqlite=3.33.0=h2a8f88b_0
-  - toml=0.10.1=py_0
-  - typed-ast=1.4.1=py39hb82d6ee_1
-  - typing_extensions=3.7.4.3=py_0
-  - tzdata=2020d=h14c3975_0
-  - vc=14.2=h21ff451_1
-  - virtualenv=20.2.2=py39hcbf5309_0
-  - vs2015_runtime=14.27.29016=h5e58377_2
-  - wheel=0.36.2=pyhd3eb1b0_0
-  - wincertstore=0.2=py39h2bbff1b_0
-  - yaml=0.2.5=he774522_0
-  - zipp=3.4.0=pyhd3eb1b0_0
-  - zlib=1.2.11=h62dcd97_4
+  - python=3.9
+  - black
+  - isort
+  - flake8
+  - mypy
+  - pre-commit
+  - psycopg2
+  - python-dotenv