web3j Exception "version must not be null"

[hayarobi]

Hot to reproduce:

1. create gradle project (or just touch gradle.properties)
2. run web3j
3. got exception like this

➜ ~> mkdir prjectA
➜ ~> cd projectA
➜ projectA> touch gradle.properties
➜ projectA> web3j
              _      _____ _
             | |    |____ (_)
__      _____| |__      / /_
\ \ /\ / / _ \ '_ \     \ \ |
 \ V  V /  __/ |_) |.___/ / |
  \_/\_/ \___|_.__/ \____/| |
                         _/ |
                        |__/
by Web3Labs
Exception in thread "main" java.lang.IllegalArgumentException: version must not be null
	at com.github.zafarkhaja.semver.Version$Validators.nonNullOrThrow(Version.java:1383)
	at com.github.zafarkhaja.semver.Version$Validators.nonNull(Version.java:1357)