Errors when running after first time in cross-dep bins workspaces

[alexcanessa]

Title	Description
Version	v0.23.2
Type	Issue
node	v10.15.0
Operating System	MacOS Mojave (10.14.4)
Short Description	bolt errors when running after the first time in cross-dep bins workspaces.
Detailed description	The original issue was that bolt didn't manage cross dependencies binary files (#126) and was fixed in #191. However, even bolt now creates the symlink, a second run will fail with the error below this table.

NOTE: Keep in mind that I'm also replicating this error via running bolt internal tests.

Error: EEXIST: file already exists, symlink '../../../bar/bin.js' -> '/private/var/folders/m3/hdz1bgz94vz5rc3x16gm7jr80000gn/T/0fd44005f5f3b1950271e2eff9b65abc/workspace-with-bin/packages/foo/node_modules/.bin/bar'

[kwelch]

We were able to work around this by declaring the bin as an object instead of a string.