Update directories requirement from >=4, <6 to >=4, <7 (#272)

---
updated-dependencies:
- dependency-name: directories
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

plotly_kaleido/Cargo.toml

@@ -31,4 +31,4 @@ plotly_kaleido = { path = ".", features = ["download"] }
 
 [build-dependencies]
 zip = "2.1"
-directories = ">=4, <6"
+directories = ">=4, <7"