Remote input files have an input.size_mb of zero

[fgvieira]

When using remote files as input, input.size_mb is 0 (as seen by disk_mb that is set to the default 1000):

rule genome_variation:
    input: https://github.com/nf-core/test-datasets/blob/rnaseq/reference/chr22_23800000-23980000.fa (retrieve from storage)
    output: temp/genome/variation/h.sapiens_chr22.1-of-2.fas
    log: logs/genome/variation/h.sapiens_chr22.1-of-2.log
    jobid: 4
    benchmark: benchmarks/genome/variation/h.sapiens_chr22.1-of-2.tsv
    reason: Missing output files: temp/genome/variation/h.sapiens_chr22.1-of-2.fas
    wildcards: name=h.sapiens_chr22, n=1, total=2
    resources: mem_mb=1, mem_mib=954, disk_mb=1000, disk_mib=954, tmpdir=<TBD>, mem=0 MiB, runtime=30