Fix building of wheels in monorepo and update docs

The main issue is that our previous hack to detect the component name
from the folder no longer works, since it'll now be an unprefixed
"client", so have the Makefile add the prefixing in.

Documentation has been updated as well.

Makefile

@@ -57,9 +57,9 @@ requirements: ## Creates requirements files for the Python projects
 
 .PHONY: build-wheels
 build-wheels: ## Builds the wheels and adds them to the wheels subdirectory
-	./scripts/verify-sha256sum-signature $$(basename ${PKG_DIR})
+	./scripts/verify-sha256sum-signature securedrop-$$(basename ${PKG_DIR})
 	./scripts/build-sync-wheels
-	./scripts/sync-sha256sums $$(basename ${PKG_DIR})
+	./scripts/sync-sha256sums securedrop-$$(basename ${PKG_DIR})
 	@echo Done!
 
 .PHONY: test

README.md

@@ -66,8 +66,8 @@ _If you don't need to deploy a package and just want to test locally, you can st
 
 ## Updating our bootstrapped build tools
 
-We use [build](https://pypa-build.readthedocs.io/en/latest/) toolchain to build our reproducible wheels.
-If we have to update the tool, use the following steps
+We use the [build](https://pypa-build.readthedocs.io/en/latest/) toolchain to build our reproducible wheels.
+If we have to update the tools, use the following steps
 
 ```shell
 # Ensure you are running in a cleanly boostrapped virtual environment
@@ -95,35 +95,31 @@ Make sure that your GPG public key is stored in `pubkeys/`, so CI can verify the
 
 ## Updating Python wheels
 
-Maintainers of `securedrop-client` and `securedrop-proxy` must ensure that
-the requirements files which are used for build of these packages (`build-requirements.txt`)
-using `make requirements` are kept up to date in latest `main` of those repositories.
-
-If new dependencies were added in the `build-requirements.txt` of that
-repo that are not in the `wheels` subdirectory for the package in this repository,
-then the maintainer needs to do the following (we are taking `securedrop-client` project
-as an example):
+When adding a new production dependency to a component, new wheels will need to be built
+plus updates to `build-requirements.txt`. This should be done after you have updated the
+dependencies in the component's `pyproject.toml` and `poetry.lock` files.
 
 ### 0. Enable the virtualenv
 
-You can create a fresh virtualenv and install the build tools from our bootstrapped wheels.
+Create a fresh virtualenv and install the build tools from our bootstrapped wheels.
 
 ```shell
 rm -rf .venv
 make install-deps
 ```
 
-Remember that the following steps needs to be done from the same virtual environment.
+The following steps needs to be done from the same virtual environment.
 
 ### 1. Create updated build-requirements.txt for the project
 
-From the `securedrop-builder` directory,
+From the `securedrop-builder` directory, run the following, where `<component>`
+is what you're trying to update dependencies for, e.g. "client", "proxy", etc.
 
 ```shell
-PKG_DIR=/home/user/code/securedrop-client make requirements
+PKG_DIR=/home/user/code/securedrop-client/<component> make requirements
 ```
 
-This will create the proper `build-requirements.txt` file in the project directory along with the binary wheel
+This will create/update the `build-requirements.txt` file in the project directory along with the binary wheel
 hashes from our own Python package index server.
 
 If we are missing any wheels from our cache/build/server, it will let you know with a following message.
@@ -151,7 +147,10 @@ PKG_DIR=/home/user/code/securedrop-client make build-wheels
 
 This above command will let you know about any new wheels + sources. It will
 build/download sources from PyPI (by verifying it against the sha256sums from
-the `requirements.txt` of the project).
+the `poetry.lock` of the project).
+
+If your package contains compiled code (e.g. C or Rust extensions), it must be
+built for all Debian versions we support.
 
 ### 3. Commit changes to the wheels directory (if only any update of wheels)