Use an int for the config version

dendrite-config.yaml

@@ -1,5 +1,8 @@
-# The config file version format
-version: v0
+# The config file format version
+# This is used by dendrite to tell if it understands the config format.
+# This will change if the structure of the config file changes or if the meaning
+# of an existing config key changes.
+version: 0
 
 # The matrix specific config
 matrix:

src/github.com/matrix-org/dendrite/common/config/config.go

@@ -30,7 +30,7 @@ import (
 
 // Version is the current version of the config format.
 // This will change whenever we make breaking changes to the config format.
-const Version = "v0"
+const Version = 0
 
 // Dendrite contains all the config used by a dendrite process.
 // Relative paths are resolved relative to the current working directory
@@ -41,7 +41,7 @@ type Dendrite struct {
 	// to update their config file to the current version.
 	// The version of the file should only be different if there has
 	// been a breaking change to the config file format.
-	Version string `yaml:"version"`
+	Version int `yaml:"version"`
 
 	// The configuration required for a matrix server.
 	Matrix struct {

src/github.com/matrix-org/dendrite/common/config/config_test.go

@@ -32,7 +32,7 @@ func TestLoadConfigRelative(t *testing.T) {
 }
 
 const testConfig = `
-version: v0
+version: 0
 matrix:
   server_name: localhost
   private_key: matrix_key.pem