chore: bump devctr version

The new container with the 1.87 toolchain is 1.87

Signed-off-by: Patrick Roy <roypat@amazon.co.uk>

Author: roypat

tools/devtool

@@ -68,7 +68,7 @@
 DEVCTR_IMAGE_NO_TAG="public.ecr.aws/firecracker/fcuvm"
 
 # Development container tag
-DEVCTR_IMAGE_TAG=${DEVCTR_IMAGE_TAG:-v80}
+DEVCTR_IMAGE_TAG=${DEVCTR_IMAGE_TAG:-v81}
 
 # Development container image (name:tag)
 # This should be updated whenever we upgrade the development container.