add linting using Hadolint · dev-sec/docker-ansible@acf4d76

SC2028 info: echo may not expand escape sequences. Use printf.

SC3009 warning: In POSIX sh, brace expansion is undefined.

SC3037 warning: In POSIX sh, echo flags are undefined.

SC3009 warning: In POSIX sh, brace expansion is undefined.

DL3042 warning: Avoid use of cache directory with pip. Use `pip install --no-cache-dir <package>`

DL3059 info: Multiple consecutive `RUN` instructions. Consider consolidation.

SC3037 warning: In POSIX sh, echo flags are undefined.

SC3009 warning: In POSIX sh, brace expansion is undefined.

DL3003 warning: Use WORKDIR to switch to a directory

SC2086 info: Double quote to prevent globbing and word splitting.

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