Update security headers

[komuw]

• The recomended minimum value strict-transport-security is 30days
• Content-Security-Policy should be in one line else it does not show up

[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (2248c3b) 74.92% compared to head (3f366c0) 74.92%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #330 +/- ## ======================================= Coverage 74.92% 74.92% ======================================= Files 43 43 Lines 4897 4897 ======================================= Hits 3669 3669 Misses 985 985 Partials 243 243 ``` | [Impacted Files](https://app.codecov.io/gh/komuw/ong/pull/330?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Komu+Wairagu) | Coverage Δ | | |---|---|---| | [middleware/security.go](https://app.codecov.io/gh/komuw/ong/pull/330?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Komu+Wairagu#diff-bWlkZGxld2FyZS9zZWN1cml0eS5nbw==) | `100.00% <100.00%> (ø)` | |

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