Improve python requirements management and create an example venv (#186)

Make use of [uv](https://docs.astral.sh/uv/) to manage python
dependencies.

Accomplish this by replacing
`load("@rules_python//python:pip.bzl", "compile_pip_requirements")` with
`load("@rules_uv//uv:pip.bzl", "pip_compile")`
This results in `bazel run //:requirements.update && bazel run
//:gazelle_python_manifest.update` having significantly improved
performance

| branch | fresh | repeated |
| --- | --- | --- |
| master | 42s | 18s |
| better_pip_rules | 24s | 2s |

So, 9x performance improvement when doing a no-op, and 2x improvement
for the "fresh" case. Not exactly the 10-100x gains claimed by uv. But
this is a bit of a different case 🤷

Also
- Update aspect_rules_py

.github/workflows/flakiness.yml

@@ -22,5 +22,5 @@ jobs:
         run: |
           # Run several times to identify flakiness, but avoid enormous tests
           # Can find them with: `bazel query 'attr(size, enormous, //...)'`
-          bazel test --runs_per_test_detects_flakes --runs_per_test=5 --test_size_filters=-enormous -- //...
+          bazel test --runs_per_test_detects_flakes --runs_per_test=5 --test_tag_filters=-skip-flakiness -- //...
       - run: echo "Status is ${{ job.status }}."

BUILD

@@ -5,9 +5,10 @@
 load("@bazel_gazelle//:def.bzl", "gazelle", "gazelle_binary")
 load("@npm//:defs.bzl", "npm_link_all_packages")
 load("@pip//:requirements.bzl", "all_whl_requirements")
-load("@rules_python//python:pip.bzl", "compile_pip_requirements")
 load("@rules_python_gazelle_plugin//manifest:defs.bzl", "gazelle_python_manifest")
 load("@rules_python_gazelle_plugin//modules_mapping:def.bzl", "modules_mapping")
+load("@rules_uv//uv:pip.bzl", "pip_compile")
+load("@rules_uv//uv:venv.bzl", "create_venv")
 
 package(default_visibility = ["//visibility:private"])
 
@@ -24,15 +25,24 @@ exports_files(
     visibility = ["//visibility:public"],
 )
 
-compile_pip_requirements(
+pip_compile(
     name = "requirements",
     # https://bazel.build/reference/be/common-definitions
-    size = "enormous",
-    timeout = "eternal",  # 60m
     requirements_in = "requirements.in",
     requirements_txt = "requirements_lock.txt",
-    # Don't want to type-check requirements building
-    tags = ["no-mypy"],
+    tags = [
+        # Don't want to type-check requirements building
+        "no-mypy",
+        # Avoid in flake detection
+        "skip-flakiness",
+    ],
+)
+
+create_venv(
+    name = "create_venv",
+    requirements_txt = "//:requirements_lock.txt",
+    # Example extras
+    site_packages_extra_files = ["//tools:utils"],
 )
 
 # This repository rule fetches the metadata for python packages we
@@ -130,6 +140,7 @@ gazelle(
 # gazelle:resolve py third_party.bazel.proto.build_event_stream_pb2 //third_party/bazel/proto:build_event_stream_py_library
 # gazelle:resolve proto pw_protobuf_protos/common.proto @pigweed//pw_protobuf:common_proto
 # gazelle:resolve py examples.pigweed.modules.blinky.blinky_pb2 //examples/pigweed/modules/blinky:blinky_pb2
+# gazelle:resolve py tools.git_pb2 //tools:git_py_library
 # gazelle:resolve py pw_cli @pigweed//pw_system/py:pw_system_lib
 # gazelle:resolve py pw_system.console @pigweed//pw_system/py:pw_system_lib
 # gazelle:resolve py pw_system.device @pigweed//pw_system/py:pw_system_lib

MODULE.bazel

@@ -18,7 +18,7 @@ bazel_dep(name = "aspect_bazel_lib", version = "2.9.4")
 ########################################
 # Set up rules_python and pip
 ########################################
-bazel_dep(name = "aspect_rules_py", version = "0.7.3")
+bazel_dep(name = "aspect_rules_py", version = "1.0.0")
 
 # Minimum version needs:
 # feat: add interpreter_version_info to py_runtime by @mattem in #1671
@@ -35,12 +35,26 @@ python.toolchain(
     python_version = PYTHON_VERSION,
 )
 
+bazel_dep(name = "rules_uv", version = "0.45.0")
+
 pip = use_extension("@rules_python//python/extensions:pip.bzl", "pip")
 pip.parse(
     hub_name = "pip",
     python_version = PYTHON_VERSION,
     requirements_lock = "//:requirements_lock.txt",
+    # Avoid building wheels with system compiler
+    # - pygraphviz
+    # download_only = True,
+    # Could put --extra-index-url here to grab my own wheels
+    # extra_pip_args = [],
 )
+
+# Could support multi-platform by specifying a different target for each
+# platform
+# --platform
+# --python-version
+# --implementation
+# --abi
 use_repo(pip, "pip")
 
 # TODO(#91): Allow bumping this up to 26 or greater while avoiding segfault