refactor requirements

.github/workflows/docs.yml

@@ -70,8 +70,7 @@ jobs:
       - name: Install Python dependencies
         run: |
           python -m pip install --user "pybind11[global]" wheel
-          python -m pip install --user --upgrade -r requirements.txt
-          python -m pip install --user --upgrade -r doc/requirements.txt
+          python -m pip install --user --upgrade -r requirements/development.txt
 
       - name: Build module
         run: |

.github/workflows/ubuntu.yml

@@ -70,7 +70,7 @@ jobs:
         run: |
             # These are needed to install black:
             python -m pip install --user --upgrade setuptools wheel
-            python -m pip install --user -r requirements.txt
+            python -m pip install --user -r requirements/development.txt
             # For sdist validation
             python -m pip install --user --upgrade twine
 

doc/misc/changelog.md

@@ -3,6 +3,13 @@
 Major changes are listed below.  Each release likely contains fiddling with back-end code,
 updates to latest `fwdpp` version, etc.
 
+## Next version
+
+Dependencies
+
+* Removed use of `pip-tools` in favor of a single `requirements/development.txt` file with loose pinning.
+  Issue {issue}`877`, PR {pr}`896`
+
 ## 0.17.1
 
 Bug fixes

doc/misc/developersguide.md

@@ -30,43 +30,13 @@ The `requirements/` folder of the source code repository contains a list of mini
 To reproduce the environments that we use for CI and deployment:
 
 ```sh
-python3 -m pip install -r requirements.txt
-# If working on the manual:
-python3 -m pip install -r doc/requirements.txt
+python3 -m pip install -r requirements/development.txt
 ```
 
-To use the latest version of the dependencies:
-
-```sh
-python3 -m pip install -r requirements.in
-# If working on the manual:
-python3 -m pip install -r doc/requirements.in
+```{note}
+It may be useful to add `--upgrade --no-cache-dir` to the above command.
 ```
 
-(sec_requirements_files)=
-
-#### Comments on "requirements" files.
-
-Python uses files with names like `requirements.txt` to specify the package environment that is expected to go along with a certain tool such as this one.
-Unfortunately, the contents of such files vary quite a bit across projects.
-
-Here, we take the files `requirements.txt` and `doc/requirements.txt` to specify completely reproducible development and production environments.
-Within these files, all dependencies are pinned to specific versions, as are the dependencies of those dependencies.
-These files specify the exact versions used for testing the package on Ubuntu environments and for building Docker containers.
-
-The files `requirements.in` and `doc/requirements.in` are looser specifications of these environments.
-Here, the dependency pinnings are minimal, trying to keep the build environment compatible with the lowest Python version number that is still supported.
-Many users working in extant Python environments may want to use the `.in` versions for installing packages.
-Some may also want to remove the installation modifications to various packages in those files.
-
-These pinnings will be updated periodically.
-
-People using `conda` to install `fwdpy11` may consider using the fully-pinned files to install dependencies using `pip`.
-
-#### Updating the CI/deployment dependencies
-
-Use `pip-compile` from [pip-tools](https://pypi.org/project/pip-tools/).
-
 ### Building the code
 
 ```sh