macos fix for github action: downgrade freetype to install 'ragg' and install binary 'units'

[kevinrue]

No description provided.

[kevinrue]

Error ragg

clang++ -arch arm64 -std=gnu++17 -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -I./agg/include -I/opt/homebrew/opt/freetype/include/freetype2 -I/opt/homebrew/opt/libpng/include/libpng16 -I/opt/homebrew/Cellar/libtiff/4.6.0/include -I/opt/homebrew/opt/zstd/include -I/opt/homebrew/Cellar/xz/5.6.2/include -I/opt/homebrew/Cellar/jpeg-turbo/3.0.3/include -I'/Users/runner/work/_temp/Library/systemfonts/include' -I'/Users/runner/work/_temp/Library/textshaping/include' -I/opt/R/arm64/include    -fPIC  -falign-functions=64 -Wall -g -O2   -c agg/src/agg_font_freetype.cpp -o agg/src/agg_font_freetype.o
agg/src/agg_font_freetype.cpp:116:18: warning: variable 'len' set but not used [-Wunused-but-set-variable]
        unsigned len = 0; 
                 ^
agg/src/agg_font_freetype.cpp:182:35: error: assigning to 'char *' from 'unsigned char *' converts between pointers to integer types where one is of the unique plain 'char' type and the other is not
            tags  = outline.tags  + first;
                    ~~~~~~~~~~~~~~^~~~~~~
1 warning and 1 error generated.
make: *** [agg/src/agg_font_freetype.o] Error 1
ERROR: compilation failed for package ‘ragg’

Fix : r-lib/ragg#170

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udunits2misses the shared object file (from Brew and compile manually) to the only solution is to get the binary