Fix surprisingly harmless typo in Dockerfile

[mcovarr]

There's a dash missing in what should be the --include argument to a git lfs pull invocation in the Dockerfile that appears to have the net effect of git lfs pull doing nothing at all. This adds back the dash so the command does what it was intended to do, but I was a bit surprised the build doesn't seem to care if the git lfs pull actually pulls anything or not. 🤔

Before:

[codecov]

Codecov Report

Merging #7806 (ecf8dbc) into master (b6a28d1) will decrease coverage by 7.357%.
The diff coverage is n/a.

@@               Coverage Diff               @@
##              master     #7806       +/-   ##
===============================================
- Coverage     86.941%   79.583%   -7.357%     
+ Complexity     36860     34813     -2047     
===============================================
  Files           2211      2211               
  Lines         173376    173376               
  Branches       18710     18710               
===============================================
- Hits          150734    137978    -12756     
- Misses         16055     28996    +12941     
+ Partials        6587      6402      -185     

Impacted Files	Coverage Δ
...adinstitute/hellbender/utils/help/TestWDLTool.java	0.000% <0.000%> (-100.000%)	⬇️
...kers/filters/VariantFiltrationIntegrationTest.java	0.658% <0.000%> (-99.342%)	⬇️
...dorientation/CollectF1R2CountsIntegrationTest.java	0.714% <0.000%> (-99.286%)	⬇️
...s/variantutils/VariantsToTableIntegrationTest.java	0.862% <0.000%> (-99.138%)	⬇️
...der/tools/walkers/sv/SVClusterIntegrationTest.java	0.500% <0.000%> (-99.000%)	⬇️
.../walkers/bqsr/BaseRecalibratorIntegrationTest.java	1.031% <0.000%> (-98.969%)	⬇️
...tion/ReferenceBlockConcordanceIntegrationTest.java	0.840% <0.000%> (-98.599%)	⬇️
...tute/hellbender/tools/FlagStatIntegrationTest.java	1.724% <0.000%> (-98.276%)	⬇️
...on/FindBreakpointEvidenceSparkIntegrationTest.java	1.754% <0.000%> (-98.246%)	⬇️
...park/pipelines/CountReadsSparkIntegrationTest.java	1.786% <0.000%> (-98.214%)	⬇️
... and 190 more

[lbergelson]

@mcovarr Huh. I'm surprised that didn't fail the docker build. I would have expected the command failing to abort it, but I guess that's not the case.

This step is not really necessary. If those files aren't checked out at build time gradle will do it for you, so that's why it didn't seem to cause any problems.

[lbergelson]

👍