* Semi-automated using `ssf-formula` (v0.5.0)
* Fix (or ignore) errors shown below:
```bash
postfix-formula$ $(grep "\- yamllint" .travis.yml | sed -e "s:^\s\+-\s\(.*\):\1:")
./postfix/osfamilymap.yaml
1:1 warning missing document start "---" (document-start)
./postfix/services.yaml
11:1 warning missing document start "---" (document-start)
12:1 warning comment not indented like content (comments-indentation)
221:1 warning comment not indented like content (comments-indentation)
./postfix/defaults.yaml
4:1 warning missing document start "---" (document-start)
pillar.example
1:1 warning missing document start "---" (document-start)
2:25 warning truthy value should be one of [false, true] (truthy)
13:17 warning truthy value should be one of [false, true] (truthy)
16:17 warning truthy value should be one of [false, true] (truthy)
22:17 warning truthy value should be one of [false, true] (truthy)
23:17 warning truthy value should be one of [false, true] (truthy)
25:17 warning truthy value should be one of [false, true] (truthy)
29:17 warning truthy value should be one of [false, true] (truthy)
31:17 warning truthy value should be one of [false, true] (truthy)
35:17 warning truthy value should be one of [false, true] (truthy)
47:15 warning truthy value should be one of [false, true] (truthy)
50:18 warning truthy value should be one of [false, true] (truthy)
53:21 warning truthy value should be one of [false, true] (truthy)
62:24 warning truthy value should be one of [false, true] (truthy)
66:31 warning truthy value should be one of [false, true] (truthy)
69:19 warning truthy value should be one of [false, true] (truthy)
70:19 warning truthy value should be one of [false, true] (truthy)
73:14 warning truthy value should be one of [false, true] (truthy)
74:21 warning truthy value should be one of [false, true] (truthy)
78:14 warning truthy value should be one of [false, true] (truthy)
89:15 error trailing spaces (trailing-spaces)
96:6 warning missing starting space in comment (comments)
130:89 error line too long (105 > 88 characters) (line-length)
131:89 error line too long (101 > 88 characters) (line-length)
152:5 error duplication of key "sender_canonical_maps" in mapping (key-duplicates)
154:5 error duplication of key "virtual_alias_maps" in mapping (key-duplicates)
190:5 error duplication of key "use_file" in mapping (key-duplicates)
235:9 error wrong indentation: expected 10 but found 8 (indentation)
248:1 error duplication of key "postfix" in mapping (key-duplicates)
258:85 error trailing spaces (trailing-spaces)
```
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