ci: Update Cargo.toml

apparently 1.171.0 is too bleeding edge

Signed-off-by: Christina Sørensen <christina@cafkafk.com>

Cargo.toml

@@ -4,7 +4,7 @@ description = "A modern replacement for ls"
 authors = ["Christina Sørensen <christina@cafkafk.com>"]
 categories = ["command-line-utilities"]
 edition = "2021"
-rust-version = "1.71.0"
+rust-version = "1.70.0"
 exclude = ["/devtools/*", "/Justfile", "/Vagrantfile", "/screenshots.png"]
 readme = "README.md"
 homepage = "https://github.com/cafkafk/eza"