Bump github.com/containers/image from 3.0.2 to 4.0.0 in /img2lambda

Bumps [github.com/containers/image](https://github.com/containers/image) from 3.0.2 to 4.0.0.
- [Release notes](https://github.com/containers/image/releases)
- [Commits](containers/image@v3.0.2...v4.0.0)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

img2lambda/Gopkg.lock

@@ -4,7 +4,7 @@
 
 [[constraint]]
   name = "github.com/containers/image"
-  version = ">= 1.3.0, < 4.0.0"
+  version = ">= 1.3.0, < 5.0.0"
 
 [[constraint]]
   name = "github.com/mattn/go-zglob"