Update README and move versioning to global inventory data

Author: Ryan McCorry

README.md

@@ -6,6 +6,8 @@ A basic [pyinfra](https://pyinfra.com) deploy that installs and optionally confi
 + Debian 8/9/10
 + CentOS 7/8
 
+This deploy installs packages in the `docker-ce` ecosystem (`docker-ce`/`docker-ce-cli`/`docker-ce-rootless-extras`) You can specify `docker_version` in your inventory data file and it will install that version for all `docker-ce` packages.
+
 ## Usage
 
 See [the example](https://github.com/Fizzadar/pyinfra-docker/tree/master/example) for a more complete example.

pyinfra_docker/docker.py

@@ -11,19 +11,21 @@
 from pyinfra.operations import apt, dnf, files, yum
 
 
-def get_pkgs_to_install(version):
+DEFAULTS = {
+    "docker_version": None,
+}
+
+
+def get_pkgs_to_install():
     docker_packages = [
         "docker-ce",
-        "docker-ce-cli"
+        "docker-ce-cli",
+        "docker-ce-rootless-extras",
     ]
-    if not version:
+    if not host.data.docker_version:
         return docker_packages
 
-    versioned_packages = []
-    for pkg in docker_packages:
-        versioned_packages.append(f"{pkg}={version}")
-
-    return versioned_packages
+    return [f"{pkg}={host.data.docker_version}" for pkg in docker_packages]
 
 
 
@@ -82,16 +84,16 @@ def _yum_or_dnf_install(yum_or_dnf, packages):
     )
 
 
-@deploy("Deploy Docker")
-def deploy_docker(config=None, version=None):
+@deploy("Deploy Docker", data_defaults=DEFAULTS)
+def deploy_docker(config=None):
     """
     Install Docker on the target machine.
 
     Args:
         config: filename or dict of JSON data
     """
 
-    packages = get_pkgs_to_install(version)
+    packages = get_pkgs_to_install()
     if host.get_fact(DebPackages):
         _apt_install(packages)
     elif host.get_fact(RpmPackages):