Fix for parse_iso_time_tz error with musl library

[fcolista]

This patch fixes the error when parsing the time in a format like:
2019-01-18T17:29:00+00:00 with musl.

This behavior is described in the issue #1609

What:

Fixes for #1609

[timopollmeier]

Hello, @fcolista! Thank you for your patch. It looks good to me, but could you also add a changelog entry in the 20.08 section, please?

[fcolista]

hi @timopollmeier thanks for your feedback!
Just to be sure, is this what you mean?

x86_64-edge:~/gitrepos/github/gvmd$ git diff
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d3557daba..3ee1d4722 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Improve VT version handling for CVE & OVAL results [#1496](https://github.com/greenbone/gvmd/pull/1496)
 - Fix migration to DB version 242 from gvmd 20.08 [#1498](https://github.com/greenbone/gvmd/pull/1498)
 - Update subject alternative name in certificate generation [#1503](https://github.com/greenbone/gvmd/pull/1503)
+- Fix for parse_iso_time_tz error with musl library [#1644](https://github.com/greenbone/gvmd/pull/1644)
 
 ### Removed
 - Remove Network Source Interface from gvmd [#1511](https://github.com/greenbone/gvmd/pull/1511)

[Dexus]

hi @timopollmeier thanks for your feedback!
Just to be sure, is this what you mean?

x86_64-edge:~/gitrepos/github/gvmd$ git diff
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d3557daba..3ee1d4722 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Improve VT version handling for CVE & OVAL results [#1496](https://github.com/greenbone/gvmd/pull/1496)
 - Fix migration to DB version 242 from gvmd 20.08 [#1498](https://github.com/greenbone/gvmd/pull/1498)
 - Update subject alternative name in certificate generation [#1503](https://github.com/greenbone/gvmd/pull/1503)
+- Fix for parse_iso_time_tz error with musl library [#1644](https://github.com/greenbone/gvmd/pull/1644)
 
 ### Removed
 - Remove Network Source Interface from gvmd [#1511](https://github.com/greenbone/gvmd/pull/1511)

Hi @fcolista he means you should add it to https://github.com/greenbone/gvmd/blob/master/CHANGELOG.md#2083-unreleased as it will backported to v20.8.3 and v21.4.3