perf build: Make minimal shellcheck version to v0.6.0

perf build: Make minimal shellcheck version to v0.6.0

The perf build failed due to the shellcheck on my machine (v0.4.6 on Ubuntu
18.04.1 LTS) doesn't support -a/--check-sourced and -S/--severity option.

These two options are introduced in shellcheck v0.4.7 and v0.6.0
respectively. So restrict the minimal version of shellcheck to v0.6.0.

Fixes: b809fc656e763296 ("perf build: Shellcheck support for OUTPUT directory")
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Junhao He <hejunhao3@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linuxarm@huawei.com
Link: https://lore.kernel.org/r/20240122080406.28678-1-yangyicong@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>