VCF header is incorrect for genotype probabilities

[cjw85]

The artic pipeline uses longshot after medaka to produce some ancilliary statistics of SARS-CoV-2 variants. The header associated with some probabilities incorrectly specifies some numbers as integer when in fact they are written as floats in teh records of the file, see nanoporetech/medaka#213

From src/print_output.rs:

let headerstr3 = format!("##INFO=<ID=PH,Number=G,Type=Integer,Description=\"PHRED-scaled Probabilities of Phased Genotypes\">

[phspo]

@cjw85 thanks for forwarding this to the correct place ;)

[vibansal]

Fixed in new release v0.4.2. Thanks.