Bump regex from 1.5.4 to 1.5.6 in /compiler/rustc_codegen_gcc#2

dependabot[bot] wants to merge 1 commit intomastersourcefrog/rust:masterfrom

dependabot/cargo/compiler/rustc_codegen_gcc/regex-1.5.6sourcefrog/rust:dependabot/cargo/compiler/rustc_codegen_gcc/regex-1.5.6Copy head branch name to clipboard