Add Epoch to blueprints/freeze version string

If the Epoch is > 0 the it should be added to the front of the version,
separated by a colon.

Also include a depsolve package with a non-zero Epoch and adjust the
tests accordingly.

internal/mocks/rpmmd/fixtures.go

@@ -157,7 +157,7 @@ func createBaseDepsolveFixture() []rpmmd.PackageSpec {
 	return []rpmmd.PackageSpec{
 		{
 			Name:    "dep-package3",
-			Epoch:   0,
+			Epoch:   7,
 			Version: "3.0.3",
 			Release: "1.fc30",
 			Arch:    "x86_64",

internal/weldr/api.go

@@ -857,7 +857,11 @@ func setPkgEVRA(dependencies []rpmmd.PackageSpec, packages []blueprint.Package)
 			return dependencies[i].Name >= pkg.Name
 		})
 		if i < len(dependencies) && dependencies[i].Name == pkg.Name {
-			packages[pkgIndex].Version = dependencies[i].Version + "-" + dependencies[i].Release + "." + dependencies[i].Arch
+			if dependencies[i].Epoch == 0 {
+				packages[pkgIndex].Version = fmt.Sprintf("%s-%s.%s", dependencies[i].Version, dependencies[i].Release, dependencies[i].Arch)
+			} else {
+				packages[pkgIndex].Version = fmt.Sprintf("%d:%s-%s.%s", dependencies[i].Epoch, dependencies[i].Version, dependencies[i].Release, dependencies[i].Arch)
+			}
 		} else {
 			// Packages should not be missing from the depsolve results
 			return fmt.Errorf("%s missing from depsolve results", pkg.Name)