Add option to set certbot version via variable

Currently the role breaks when the hard coded version is missing from
the ppa.
This adds the option to specify the version to be installed via a variable.

Author: fapdash

README.md

@@ -15,6 +15,8 @@ Role Variables
 domain_name: www.mydomain.io
 letsencrypt_email: myaccount@letsencrypt.org
 certbot_nginx_cert_name: mycert # optional
+certbot_version: 0.31.0-1+ubuntu{{ ansible_distribution_version }}.1+certbot+1 # optional
+certbot_nginx_version: 0.31.0-1+ubuntu{{ ansible_distribution_version }}.1+certbot+1 # optional
 ```
 
 if set, `certbot_nginx_cert_name`'s value will be passed to the certbot's `--cert-name` argument, which is used to identify the certificate in certbot command such as `certbot delete`. You will see a list of certificates identified with this name by running `certbot certificates`. This name will also be used as the file paths for the certificate in `/etc/letsencrypt/live/`.

defaults/main.yml

@@ -1,2 +1,4 @@
 ---
 letsencrypt_staging: false
+certbot_version: 0.31.0-1+ubuntu{{ ansible_distribution_version }}.1+certbot+1
+certbot_nginx_version: 0.31.0-1+ubuntu{{ ansible_distribution_version }}.1+certbot+1

tasks/main.yml

@@ -6,12 +6,12 @@
 
 - name: Install certbot
   package:
-    name: "certbot=0.31.0-1+ubuntu{{ ansible_distribution_version }}.1+certbot+1"
+    name: "certbot={{ certbot_version }}"
     state: present
 
 - name: Install certbot-nginx plugin
   package:
-    name: "python-certbot-nginx=0.31.0-1+ubuntu{{ ansible_distribution_version }}.1+certbot+1"
+    name: "python-certbot-nginx={{ certbot_nginx_version }}"
     state: present
 
 - import_tasks: certificate.yml