Fix issue when the mode isn't present

- Can happen with this kind of diff

  ```diff
  diff --git a/blabla.rb b/app/my_file.rb
  similarity index 100%
  rename from blabla.rb
  rename to app/my_file.rb
  ```

CHANGELOG.md

@@ -6,6 +6,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+## [1.1.1] - 2024-2-21
+### Fixed
+- `GithubDiffParser::Diff#new_mode?` and ``GithubDiffParser::Diff#deleted_mode?` would raise
+  an error with this kind of diff:
+
+  ```diff
+  diff --git a/blabla.rb b/app/my_file.rb
+  similarity index 100%
+  rename from blabla.rb
+  rename to app/my_file.rb
+  ```
+
 ## [1.1.0] - 2024-2-21
 ### Added
 - Github Diff Parser parses the permissions bits and you now have have access to various method

lib/github_diff_parser/diff.rb

@@ -78,7 +78,7 @@ def add_line(line_content, type:)
     #
     # @return [Boolean]
     def deleted_mode?
-      @mode.operation == "deleted"
+      @mode&.operation == "deleted"
     end
 
     # Check if this Diff is set to new mode.
@@ -94,7 +94,7 @@ def deleted_mode?
     #
     # @return [Boolean]
     def new_mode?
-      @mode.operation == "new"
+      @mode&.operation == "new"
     end
 
     # Check if this Diff is set to rename mode.
@@ -112,17 +112,17 @@ def rename_mode?
 
     # @return [Boolean] True if this diff applies to a regular file.
     def normal_file?
-      @mode.bits == "100644"
+      @mode&.bits == "100644"
     end
 
     # @return [Boolean] True if this diff applies to an executable.
     def executable?
-      @mode.bits == "100755"
+      @mode&.bits == "100755"
     end
 
     # @return [Boolean] True if this diff applies to a symlink.
     def symlink?
-      @mode.bits == "120000"
+      @mode&.bits == "120000"
     end
 
     # @return [String] The source of the symlink

test/github_diff_parser_test.rb

@@ -408,6 +408,11 @@ def test_file_moved
     assert_equal("app/my_file.rb", parsed_diff.new_filename)
     assert_equal(0, parsed_diff.hunks.count)
     assert_predicate(parsed_diff, :rename_mode?)
+    refute_predicate(parsed_diff, :new_mode?)
+    refute_predicate(parsed_diff, :deleted_mode?)
+    refute_predicate(parsed_diff, :normal_file?)
+    refute_predicate(parsed_diff, :symlink?)
+    refute_predicate(parsed_diff, :executable?)
   end
 
   def test_rails_diff