refactor to mautrix 0.17.x; update deps

vendor/maunium.net/go/mautrix/crypto/goolm/base64.go

@@ -0,0 +1,22 @@
+package goolm
+
+import (
+	"encoding/base64"
+)
+
+// Deprecated: base64.RawStdEncoding should be used directly
+func Base64Decode(input []byte) ([]byte, error) {
+	decoded := make([]byte, base64.RawStdEncoding.DecodedLen(len(input)))
+	writtenBytes, err := base64.RawStdEncoding.Decode(decoded, input)
+	if err != nil {
+		return nil, err
+	}
+	return decoded[:writtenBytes], nil
+}
+
+// Deprecated: base64.RawStdEncoding should be used directly
+func Base64Encode(input []byte) []byte {
+	encoded := make([]byte, base64.RawStdEncoding.EncodedLen(len(input)))
+	base64.RawStdEncoding.Encode(encoded, input)
+	return encoded
+}