Merge branch 'telegraf-1.15' into 'master'

Telegraf 1.15

See merge request !371

roles/telegraf/tasks/main.yml

 - name: Install Telegraf from URL [RHEL/CentOS]
   yum:
     name: "{{ telegraf_install_rpm_url }}"
-    state: present
+    state: latest
   when: ansible_os_family == "RedHat"
   become: true
   become_user: root
@@ -17,7 +17,7 @@
 - name: Install Telegraf package
   apt:
     deb: /tmp/telegraf-ansible-download.deb
-    state: present
+    state: latest
   when: ansible_os_family == "Debian"
   become: true
   become_user: root