fix(playbooks): wkhtmltopdf checksum string for debian 9 (frappe#969)

* Update main.yml

Correcting checksum string for Debian 9

* fix(playbook): yaml syntax for checksum in wkhtmltopdf

Co-authored-by: gavin <gavin18d@gmail.com>

playbooks/roles/wkhtmltopdf/tasks/main.yml

@@ -72,7 +72,7 @@
   get_url:
     url: https://github.com/wkhtmltopdf/wkhtmltopdf/releases/download/0.12.5/wkhtmltox_0.12.5-1.stretch_{{ "amd64" if ansible_architecture == "x86_64" else "i386"}}.deb
     dest: /tmp/wkhtmltox.deb
-    checksum: '{{ 1140b0ab02aa6e17346af2f14ed0de807376de475ba90e1db3975f112fbd20bb if ansible_architecture == "x86_64" else 5b2d15e738ac479e7a8ca6fd765f406c3684a48091813520f87878278d6dd22a }}'
+    checksum: "sha256:{{ '1140b0ab02aa6e17346af2f14ed0de807376de475ba90e1db3975f112fbd20bb' if ansible_architecture == 'x86_64' else '5b2d15e738ac479e7a8ca6fd765f406c3684a48091813520f87878278d6dd22a' }}"
   when: ansible_distribution == 'Debian' and ansible_distribution_major_version == '9'
 
 - name: download wkthmltox Debian 10
@@ -92,4 +92,4 @@
      deb: /tmp/wkhtmltox.deb
      state: present
   when: ansible_os_family == 'Debian'
-...
+...