docs: add PyPI resource and pyproject autodiscovery documentation (#2769)

Add documentation for two new plugins:
- pypi resource: PyPI registry interaction (source, condition)
- pyproject autodiscovery: Python dependency updates via pyproject.toml + uv

Signed-off-by: Loïs Postula <lois@postu.la>
Co-authored-by: Olivier Vernin <olivier@vernin.me>

Author: loispostula

assets/code_example/docs/plugins/resources/pypi/updatecli.d/default.yaml

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+name: PyPI resource example
+sources:
+  requests:
+    name: Get latest requests version from PyPI
+    kind: pypi
+    spec:
+      name: requests
+  flask:
+    name: Get latest flask version matching >=3.0
+    kind: pypi
+    spec:
+      name: flask
+      versionfilter:
+        kind: semver
+        pattern: ">=3.0.0"
+conditions:
+  requests:
+    name: Test that requests version 2.31.0 exists on PyPI
+    kind: pypi
+    disablesourceinput: true
+    spec:
+      name: requests
+      version: 2.31.0
+targets:
+  # Targets are not supported

content/en/docs/plugins/autodiscovery/pyproject.adoc

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+---
+title: "Pyproject"
+description: "Discover Python dependency updates from pyproject.toml"
+lead: "kind: pyproject"
+draft: false
+images: []
+menu:
+  docs:
+    parent: "plugin-autodiscovery"
+weight: 131
+toc: true
+plugins:
+  - autodiscovery
+---
+
+== Description
+
+The pyproject crawler looks recursively for all Python dependencies from `pyproject.toml` files.
+It detects the package manager in use via lock files (currently `uv.lock` is supported) and generates manifests to update dependencies using the appropriate tool.
+
+Dependencies are discovered from both `[project.dependencies]` and `[project.optional-dependencies]` sections. PEP 508 dependency strings are parsed to extract package names and version constraints. Environment markers are stripped.
+
+Generated manifests use the `pypi` resource as a source and `uv add` as a shell target, which atomically updates both `pyproject.toml` and `uv.lock`.
+
+== Manifest
+=== Parameters
+
+{{< autodiscoveryparameters "pyproject" >}}
+
+==== Example
+
+===== Basic Example
+
+[source,yaml]
+----
+# updatecli.d/pyproject.yaml
+autodiscovery:
+  crawlers:
+    pyproject:
+      rootdir: "."
+      versionfilter:
+        kind: semver
+        pattern: minor
+----
+
+===== Filter to Specific Packages
+
+[source,yaml]
+----
+# updatecli.d/pyproject-only.yaml
+autodiscovery:
+  crawlers:
+    pyproject:
+      only:
+        - packages:
+            "requests": ""
+            "flask": ""
+----
+
+===== Private PyPI Registry
+
+[source,yaml]
+----
+# updatecli.d/pyproject-private.yaml
+autodiscovery:
+  crawlers:
+    pyproject:
+      rootdir: "."
+      # Custom PyPI index URL propagated to all generated pypi source specs
+      indexurl: "https://pypi.example.com/"
+      versionfilter:
+        kind: semver
+        pattern: ">=1.0.0"
+----
+
+NOTE: The `indexurl` parameter is propagated to all generated pypi resource specs, allowing consistent registry configuration across all discovered dependencies. For private registry authentication, the `pypi` resource supports a `token` field for Bearer token auth.
+
+NOTE: The alias `python/uv` can also be used instead of `pyproject`.

content/en/docs/plugins/resource/pypi.adoc

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+---
+title: "PyPI"
+description: "Interact with the PyPI registry"
+lead: "kind: pypi"
+date: 2026-03-25T00:00:00+00:00
+draft: false
+images: []
+menu:
+  docs:
+    parent: "plugin-resource"
+toc: true
+plugins:
+  - source
+  - condition
+---
+// <!-- Required for asciidoctor -->
+:toc:
+// Set toclevels to be at least your hugo [markup.tableOfContents.endLevel] config key
+:toclevels: 4
+
+[cols="1^,1^,1^",options=header]
+|===
+| source | condition | target
+| &#10004; | &#10004; | &#10007;
+|===
+
+**source**
+
+The PyPI "source" retrieves the latest version of a Python package from a PyPI-compatible registry matching a specific version filter. PEP 440 pre-release versions (alpha, beta, rc) are automatically normalized to semver for filtering.
+
+**condition**
+
+The PyPI "condition" tests that a specific version exists on a PyPI-compatible registry.
+
+**target**
+
+The PyPI "target" is not supported.
+
+== Parameter
+
+{{< resourceparameters "sources" "pypi" >}}
+
+== Example
+
+[source,yaml]
+----
+# updatecli.yaml
+{{<include "assets/code_example/docs/plugins/resources/pypi/updatecli.d/default.yaml">}}
+----