bake: support compose inline dockerfile

compose-go v1.13.0 supports the new dockerfile_inline to allow including
a dockerfile inline in the compose definition, so we should map this to
bake's dockerfile-inline property.

Signed-off-by: Justin Chadwell <me@jedevc.com>

bake/compose.go

@@ -69,6 +69,11 @@ func ParseCompose(cfgs []compose.ConfigFile, envs map[string]string) (*Config, e
 				dockerfilePath := s.Build.Dockerfile
 				dockerfilePathP = &dockerfilePath
 			}
+			var dockerfileInlineP *string
+			if s.Build.DockerfileInline != "" {
+				dockerfileInline := s.Build.DockerfileInline
+				dockerfileInlineP = &dockerfileInline
+			}
 
 			var secrets []string
 			for _, bs := range s.Build.Secrets {
@@ -88,11 +93,12 @@ func ParseCompose(cfgs []compose.ConfigFile, envs map[string]string) (*Config, e
 
 			g.Targets = append(g.Targets, targetName)
 			t := &Target{
-				Name:       targetName,
-				Context:    contextPathP,
-				Dockerfile: dockerfilePathP,
-				Tags:       s.Build.Tags,
-				Labels:     labels,
+				Name:             targetName,
+				Context:          contextPathP,
+				Dockerfile:       dockerfilePathP,
+				DockerfileInline: dockerfileInlineP,
+				Tags:             s.Build.Tags,
+				Labels:           labels,
 				Args: flatten(s.Build.Args.Resolve(func(val string) (string, bool) {
 					if val, ok := s.Environment[val]; ok && val != nil {
 						return *val, true