Merge pull request #1089 from RcppCore/feature/docker_3.6

simple change to define a Docker target for R 3.6.3

Author: eddelbuettel

docker/ci-3.6/Dockerfile

@@ -0,0 +1,17 @@
+## Emacs, make this -*- mode: sh; -*-
+
+FROM r-base:3.6.3
+
+LABEL org.label-schema.license="GPL-2.0" \
+      org.label-schema.vcs-url="https://github.com/RcppCore/Rcpp" \
+      maintainer="Dirk Eddelbuettel <[email protected]>"
+
+RUN apt-get update \
+        && apt-get install -y --no-install-recommends git \
+        && install.r inline pkgKitten rbenchmark tinytest
+
+ENV _R_CHECK_FORCE_SUGGESTS_ FALSE
+ENV _R_CHECK_TESTS_NLINES_ 0
+ENV RunAllRcppTests yes
+
+CMD ["bash"]