libb64: update to 2.0.0.1

libb64: update to 2.0.0.1

Patch release fixing build system issues with the 2.0.0 release.
2.0.0 introduced API changes including:
 * Version macros for detection of incompatible API / version
 * size_t as argument to allow longer base64 encoded strings
 * Configurable line break functionality
 * Flags field for encoder
 * Helpers to calculate required output buffer maximum lengths
 * Switched in-/out-pointers to void*

Link: https://github.com/libb64/libb64/blob/v2.0.0.1/CHANGELOG.md
Signed-off-by: Daniel Golle <redacted>