README: add dependency protobuf-c-compiler

This dependency is required for the Knot Resolver's dnstap module.

README.adoc

@@ -40,7 +40,7 @@ You need to have a GNU/Linux distribution to be able to compile Turris OS and pa
 To install all dependencies for Debian distribution, you can use:
 
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-apt install ca-certificates git build-essential zlib1g-dev gawk libssl-dev subversion unzip libncurses-dev wget python python3 file rsync gcc-multilib g++-multilib libc6-dev-i386
+apt install ca-certificates git build-essential zlib1g-dev gawk libssl-dev subversion unzip libncurses-dev wget python python3 file rsync gcc-multilib g++-multilib libc6-dev-i386 protobuf-c-compiler
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 For other distributions, we suggest to look at