`ssh-agent` & `ssh-add` is missing from python-semantic-release github action

Question

I've been using python-semantic-release to deploy my open source packages for years now, but recently the jobs started failing because ssh-agent and ssh-add are apparently unavailable. Has something changed, such that I need to install the openssh-client before calling the tool? Or is this something that should be handled within the python-semantic-release GitHub Action?

Configuration

Semantic Release Configuration

[tool.semantic_release]
build_command = "python3 -m pip install poetry && poetry build"
commit_message = """
chore: Release v{version}

Automatically generated by python-semantic-release."""
version_variables = [
    "doc/source/conf.py:version",
    "reverse_argparse/__init__.py:__version__",
]
version_toml = [
    "pyproject.toml:tool.poetry.version",
]


[tool.semantic_release.branches.master]
match = "master"


[tool.semantic_release.changelog]
exclude_commit_patterns = [
    "chore.*deps.*Bump",
    "Merge pull request",
    "ci.*pre-commit.*auto-update",
]


[tool.semantic_release.commit_author]
env = "GIT_COMMIT_AUTHOR"
default = "semantic-release <semantic-release>"


[tool.semantic_release.commit_parser_options]
allowed_tags = [
    "build",
    "chore",
    "ci",
    "docs",
    "feat",
    "fix",
    "minor",
    "patch",
    "perf",
    "refactor",
    "style",
    "test",
]
minor_tags = ["feat", "minor"]
patch_tags = ["fix", "patch", "perf"]

See also my pyproject.toml for fuller details.

Additional context

Here's a failing job from this workflow configuration, which yields

...
 SSH Key pair found, configuring signing...
mkdir: created directory '/github/home/.ssh'
***
4d04b340ba4ac06a205eb7fb725a9c0ad4211a20ae54ba953ab0bf267d0279bf  /github/home/.ssh/signing_key
/usr/local/bin/action-entrypoint: line 159: ssh-agent: command not found
/usr/local/bin/action-entrypoint: line 160: ssh-add: command not found

I tried adding

      - name: Install openssh-client
        run: sudo apt-get update && sudo apt-get install -y openssh-client

right before the python-semantic-release GitHub Action, but that didn't change the behavior.