Add support of GPSHPositioningError

[Stefal]

Hi!

I'm not a Java developer at all. I've done my best to understand the code and add the support of the GPSHPositioningError tag. This tag seems available since Exif 2.3

GPSHPositioningError
This tag indicates horizontal positioning errors in meters.
Tag = 31 (1F.H)
Type = RATIONAL
Count = 1
Default = None

Note When the tag Type is ASCII, it shall be terminated with NULL.
It shall be noted carefully that since the value count includes the terminator NULL, the total
count is the number of data+1. For example, GPSLatitudeRef cannot have any values other
than Type ASCII 'N' or 'S'; but because the terminator NULL is added, the value of N is 2.

[garydgregory]

Hello @Stefal

Thank you for your PR.

New public and protected elements should have a Javadoc comment that includes a since tag.

This PR needs a unit test to prove the change does what you think it does.

It's OK to include an image with the test as long as it is yours, or if not, its license is Apache 2.0 or compatible with the Apache license.

[Stefal]

I didn't add a Javadoc because there isn't one in the file, nor a test.

I wrote the test with the help of WebPMetadataTest.java and MetadataExample.java. I hope it's not too bad.

edit: BTW, which latest Exif release is supported ? 2.31 ?

[garydgregory]

Hello @Stefal

Thank you for your updates.

Please run mvn before you push to run and fix all build checks.

I'm not sure which exact version of Exif we support but that would be good to document.

[Stefal]

Hello @garydgregory

I've fixed the 2 CheckStyle errors Maven reported.