fix(docker): add brotli to the Falco image

[LucaGuerra]

What type of PR is this?

Uncomment one (or more) /kind <> lines:

/kind bug

Any specific area of the project related to this PR?

Uncomment one (or more) /area <> lines:

/area build

What this PR does / why we need it:

Fixes the image falcosecurity/falco:master which is currently experimenting technical difficulties:

/usr/bin/falco: error while loading shared libraries: libbrotlienc.so.1: cannot open shared object file: No such file or directory

/ # ldd /usr/bin/falco
        linux-vdso.so.1 (0x00007ffc3f1f9000)
        libelf.so.1 => /usr/lib/libelf.so.1 (0x00007e2b45b03000)
        libbrotlicommon.so.1 => /usr/lib/libbrotlicommon.so.1 (0x00007e2b45ae0000)
        libbrotlienc.so.1 => not found
        libbrotlidec.so.1 => /usr/lib/libbrotlidec.so.1 (0x00007e2b45ad3000)
        libm.so.6 => /lib/libm.so.6 (0x00007e2b459f1000)
        libpthread.so.0 => /lib/libpthread.so.0 (0x00007e2b459ea000)
        libc.so.6 => /lib/libc.so.6 (0x00007e2b457f5000)
        libdl.so.2 => /lib/libdl.so.2 (0x00007e2b457f0000)
        librt.so.1 => /lib/librt.so.1 (0x00007e2b457eb000)
        /lib64/ld-linux-x86-64.so.2 (0x00007e2b45b25000)
        libz.so.1 => /lib/libz.so.1 (0x00007e2b457d1000)
        libzstd.so.1 => /usr/lib/libzstd.so.1 (0x00007e2b4572f000)

Actually I think libbrotli shouldn't even be there. I will investigate further but this fixes it for the time being.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

fix(docker): add brotli to the Falco image

[FedeDP]

/approve

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: FedeDP, LucaGuerra

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[poiana]

LGTM label has been added.

Git tree hash: 07db26f61e4ad1317ae1d118822457ea6f667c3c

[FedeDP]

/milestone 0.40.0