build.sh referencing non-existent External directory

[ShukantPal]

https://github.com/GPUOpen-Tools/compressonator/blob/cb281b97eb05e35ec739a462c71524c4b1eefae3/scripts/build.sh#L7

Should probably be ${COMPRESSONATOR_PROJECT_DIR}/external/build , since the top-level directory External is actually external now.

[ShukantPal]

I get https://github.com/GPUOpen-Tools/compressonator/blob/cb281b97eb05e35ec739a462c71524c4b1eefae3/scripts/build.sh#L40

#16 0.210 + cmake /trees/Compressonator/External/cmake -DCOMPRESSONATOR_PROJECT_DIR:STRING=/trees/Compressonator -DCMAKE_BUILD_TYPE:STRING=Release -DCLEAN_BUILD:BOOL=OFF #16 0.258 CMake Error: The source directory "/trees/Compressonator/External/cmake" does not exist.

[NavNTCMP]

@ShukantPal Issue addressed in v4.5 release