Use omissis/go-jsonschema image for type generation (#545)

Generate types from the JSON schema using the
official`omissis/go-jsonschema` image instead of the custom
`surjection/go-jsonschema` image.

We built and used the `surjection/go-jsonschema` image because we needed
a feature that was not yet released in `omissis/go-jsonschema`:

omissis/go-jsonschema#220

Now that the feature is available in the `omissis/go-jsonschema` `0.17`
[release](https://github.com/omissis/go-jsonschema/releases/tag/v0.17.0)
we can switch back to using it.

Makefile

@@ -15,9 +15,7 @@ format:
 
 generate: format
 	# Generate the types from the JSON schema
-	# Temporarily use the `surjection/go-jsonschema` image because we need https://github.com/omissis/go-jsonschema/pull/220
-	# Use the official `omissis/gojsonschema` image once 0.17.0 is released.
-	docker run --rm -v $$PWD/schema.json:/mnt/schema.json surjection/go-jsonschema:0.16.1 --only-models -p migrations --tags json /mnt/schema.json > pkg/migrations/types.go
+	docker run --rm -v $$PWD/schema.json:/mnt/schema.json omissis/go-jsonschema:0.17.0 --only-models -p migrations --tags json /mnt/schema.json > pkg/migrations/types.go
 
 	# Add the license header
 	echo "// SPDX-License-Identifier: Apache-2.0" | cat - pkg/migrations/types.go > pkg/migrations/types.go.tmp