aws_util: fix leading zeros in time_key strings

[kangaechu]

This PR fixes leading zeros in time_key strings.

The kinesis_datastream/kinesis_firehose ouput plugin can add timestamps by specifying the time_key/time_key_format parameters.

Format qualifiers include %3N for milliseconds and %9N / %L for nanoseconds.

In the current implementation, the number of digits in the timestamp is insufficient when milliseconds are smaller than 100 ms (e.g., 0xx / 00x ) or nanoseconds are smaller than 100 ms (e.g., 0xxxxxxxxxxx / 00xxxxxxxxx ).

Therefore, the number of digits has been corrected to be correct.

This fix was opened by @PettitWesley in #8116, but there have been no changes for about 6 months, and I was troubled that this problem was not resolved.

Therefore, I created a new Pull request.

• Fixes kinesis_streams plugin truncates time_key when using millsecond precision format #7538
• Fixes aws_util: fix leading zeros in time_key #8116

---

Enter [N/A] in the box, if an item is not applicable to your change.

Testing
Before we can approve your change; please submit the following in a comment:

• [N/A] Example configuration file for the change
• [N/A] Debug log output from testing the change

• [N/A] Attached Valgrind output that shows no leaks or memory corruption was found

If this is a change to packaging of containers or native binaries then please confirm it works for all targets.

• [N/A] Run local packaging test showing all targets (including any new ones) build.
• [N/A] Set ok-package-test label to test for all targets (requires maintainer to do).

Documentation

• [N/A] Documentation required for this feature

Backporting

• [N/A] Backport to latest stable release.

---

Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

[kangaechu]

@PettitWesley Would you review this PR?

[kangaechu]

@edsiper Would you review this PR?
@PettitWesley Mr. A is the code owner of this file, but does not seem to be responding to mentions.

[leonardo-albertovich]

According to the documentation this change is correct.

[edsiper]

thank you