bcftools: add singularity files

src/singularity_modules/bcftools/1.7/bcftools.def

+Bootstrap: docker
+From: ubuntu:18.04
+
+%labels
+MAINTAINER Laurent Modolo
+
+%post
+BCFTOOLS_VERSION=1.7
+PACKAGES=bcftools=${BCFTOOLS_VERSION}*
+
+apt-get update && \
+apt-get install -y --no-install-recommends ${PACKAGES} && \
+apt-get clean
+
+%environment
+export BCFTOOLS_VERSION=1.7
+
+%runscript
+exec /bin/bash "$@"

src/singularity_modules/bcftools/1.7/build.sh

+#/bin/sh
+sudo singularity build --force bin/bcftools:1.7.sif src/singularity_modules/bcftools/1.7/bcftools.def
+singularity sign bin/bcftools:1.7.sif