* Bump ubuntu docker build to bionic

Fixes build dependency for arm64
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>

* Add Build-Depends: dh-python

Fixes build dependency issue observed on bionic/arm64:

dh: unable to load addon python3: Can't locate Debian/Debhelper/Sequence/python3.pm in @INC (you may need to install the Debian::Debhelper::Sequence::python3 module) (@INC contains: /etc/perl /usr/local/lib/aarch64-linux-gnu/perl/5.26.1 /usr/local/share/perl/5.26.1 /usr/lib/aarch64-linux-gnu/perl5/5.26 /usr/share/perl5 /usr/lib/aarch64-linux-gnu/perl/5.26 /usr/share/perl/5.26 /usr/local/lib/site_perl /usr/lib/aarch64-linux-gnu/perl-base) at (eval 9) line 1.
BEGIN failed--compilation aborted at (eval 9) line 1.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>

* Enable arm64 deb packaging

LLVM6.0 is minimum version required for arm64 build. [PR#1512]

[PR#1512] https://github.com/iovisor/bcc/pull/1512Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>