ci(yamllint): add rule `empty-values` & use new `yaml-files` setting

[myii]

• Semi-automated using https://github.com/myii/ssf-formula/pull/27
• Fix errors shown below:

bind-formula$ yamllint -s .
./pillar-with-views.example
  1:1       warning  missing document start "---"  (document-start)
  2:89      error    line too long (93 > 88 characters)  (line-length)
  4:89      error    line too long (98 > 88 characters)  (line-length)
  5:51      warning  comment not indented like content  (comments-indentation)
  5:89      error    line too long (90 > 88 characters)  (line-length)
  6:1       error    trailing spaces  (trailing-spaces)
  8:89      error    line too long (104 > 88 characters)  (line-length)
  10:89     error    line too long (104 > 88 characters)  (line-length)
  11:89     error    line too long (114 > 88 characters)  (line-length)
  12:89     error    line too long (116 > 88 characters)  (line-length)
  14:1      error    trailing spaces  (trailing-spaces)
  16:89     error    line too long (121 > 88 characters)  (line-length)
  18:89     error    line too long (108 > 88 characters)  (line-length)
  20:89     error    line too long (97 > 88 characters)  (line-length)
  22:89     error    line too long (106 > 88 characters)  (line-length)
  23:22     warning  truthy value should be one of [false, true]  (truthy)
  23:89     error    line too long (97 > 88 characters)  (line-length)
  24:51     warning  comment not indented like content  (comments-indentation)
  24:89     error    line too long (110 > 88 characters)  (line-length)
  24:110    error    trailing spaces  (trailing-spaces)
  25:89     error    line too long (122 > 88 characters)  (line-length)
  26:19     warning  truthy value should be one of [false, true]  (truthy)
  27:19     warning  truthy value should be one of [false, true]  (truthy)
  29:89     error    line too long (113 > 88 characters)  (line-length)
  31:89     error    line too long (98 > 88 characters)  (line-length)
  33:89     error    line too long (104 > 88 characters)  (line-length)
  35:89     error    line too long (101 > 88 characters)  (line-length)
  36:51     warning  comment not indented like content  (comments-indentation)
  36:89     error    line too long (112 > 88 characters)  (line-length)
  36:112    error    trailing spaces  (trailing-spaces)
  37:89     error    line too long (122 > 88 characters)  (line-length)
  38:22     warning  truthy value should be one of [false, true]  (truthy)
  39:19     warning  truthy value should be one of [false, true]  (truthy)
  40:19     warning  truthy value should be one of [false, true]  (truthy)
  43:89     error    line too long (96 > 88 characters)  (line-length)
  44:89     error    line too long (119 > 88 characters)  (line-length)
  45:51     warning  comment not indented like content  (comments-indentation)
  46:1      error    trailing spaces  (trailing-spaces)
  50:89     error    line too long (99 > 88 characters)  (line-length)
  57:89     error    line too long (89 > 88 characters)  (line-length)
  70:1      error    trailing spaces  (trailing-spaces)
  71:89     error    line too long (96 > 88 characters)  (line-length)
  72:89     error    line too long (119 > 88 characters)  (line-length)
  73:51     warning  comment not indented like content  (comments-indentation)
  74:1      error    trailing spaces  (trailing-spaces)
  78:89     error    line too long (99 > 88 characters)  (line-length)
  85:89     error    line too long (89 > 88 characters)  (line-length)
  87:89     error    line too long (110 > 88 characters)  (line-length)

[myii]

Need to fix before merging:

        yamllint:
          ignore:
            additional:
              - pillar-with-views.example

[myii]

Fixed as shown in the updated first comment.

[saltstack-formulas-travis]

:tada: This PR is included in version 0.18.3 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: