chore: speed up pre-commit initialization

The pre-commit "environments" (dependencies) now get installed during image build rather than devcontainer start. This shaves a minute off the start time on my machine.

.devcontainer/Dockerfile

@@ -20,3 +20,10 @@ RUN pip install -r docs/requirements.txt
 
 COPY tests/pytest/requirements.txt tests/pytest/requirements.txt
 RUN pip install -r tests/pytest/requirements.txt
+
+# install pre-commit environments in throwaway Git repository
+# https://stackoverflow.com/a/68758943
+COPY .pre-commit-config.yaml .
+RUN git init . && \
+    pre-commit install-hooks && \
+    rm -rf .git

.devcontainer/postAttach.sh

@@ -1,11 +1,8 @@
 #!/usr/bin/env bash
 set -eu
 
-# initialize hook environments
-pre-commit install --install-hooks --overwrite
-
-# manage commit-msg hooks
-pre-commit install --hook-type commit-msg
+# initialize pre-commit
+pre-commit install --overwrite
 
 # install cypress
 cd tests/cypress && npm install && npx cypress install

.pre-commit-config.yaml

@@ -1,3 +1,6 @@
+default_install_hook_types:
+  - pre-commit
+  - commit-msg
 repos:
   - repo: https://github.com/compilerla/conventional-pre-commit
     rev: v1.2.0