package/zstd: bump to version 1.4.5

package/zstd: bump to version 1.4.5

- Get official tarball and its hash
- Update indentation in hash file (two spaces)

This is a fairly important release which includes performance
improvements and new major CLI features. It also fixes a few corner
cases, making it a recommended upgrade.

https://github.com/facebook/zstd/releases/tag/v1.4.5
https://github.com/facebook/zstd/releases/tag/v1.4.4

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>