ci: Update battery and the tool chain
Debian made gcc-8 the default which breaks the battery build, so update battery to the latest version and move to the gcc-9 and clang-8 tool chains.
Edited by Gert Wollny
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Debian made gcc-8 the default which breaks the battery build, so update battery to the latest version and move to the gcc-9 and clang-8 tool chains.