Use variable for gpg fingerprint

Using the fingerprint in the rpm_key module requires Ansible 2.9. Updated meta file to reflect this requirement.

tasks/install/Debian.yml

@@ -1,7 +1,7 @@
 - name: Add ZeroTier PGP key
   apt_key:
     url: "{{ zerotier_gpg_url }}"
-    id: "0x74A5E9C458E1A431F1DA57A71657198823E52A61"
+    id: "{{ zerotier_gpg_fingerprint }}"
 
 - name: Check if Ubuntu release has dedicated repo
   uri:

tasks/install/RedHat.yml

@@ -2,6 +2,7 @@
   rpm_key:
     state: present
     key: "{{ zerotier_gpg_url }}"
+    fingerprint: "{{ zerotier_gpg_fingerprint }}"
 
 - name: Add ZeroTier repo for RHEL/CentOS
   yum_repository: