x11/swww: Update to 0.10.3

• Update list of build dependencies
• Use the variable CARGO_INSTALL_PATH to fix the build that otherwise fails with the error:

> Generating temporary packing list

error: found a virtual manifest at /usr/local/poudriere/ports/default/x11/swww/work/swww-0.10.3/Cargo.toml instead of a package manifest

• Error code 101

• Add pkg-message (shown when upgrading from a version lesser than 0.10)

Release changes: https://github.com/LGFae/swww/releases/tag/v0.10.3
Reported by: Leonardo Gibrowski Faé <notifications@github.com>