Update API support to version 4

[dkocher]

Support current API version 4.

https://www.backblaze.com/docs/cloud-storage-native-api-versions

This change allows to access B2 with

• Multi-Bucket Application Keys that grant access to a specific group of buckets within an account, including the option to limit access based on a single file prefix

[dkocher]

Created upstream issue ¹.

Footnotes

1. Update for Native API version 4 backblaze-b2-java-api#8 ↩

[dkocher]

Depends on

• Update for Native API version 4 backblaze-b2-java-api#10