feat: add 'single_step' mode

This is an optional mode where the version number will only be incremented by the minimum possible amount, regardless of how many underlying commits there were.
For example, assume the last release was v1.2.3 and your commit log is as follows:

  fix: ...
  feat: ...
  fix: ...
  fix: ...

If single_step is false (the default), this will result in the generated next version v1.3.2.
Setting single_step to true, however, will result in the version v1.3.0.

lib/fastlane/plugin/semantic_release/actions/analyze_commits.rb

@@ -80,6 +80,12 @@ def self.is_releasable(params)
         next_minor = (version.split('.')[1] || 0).to_i
         next_patch = (version.split('.')[2] || 0).to_i
 
+        # setup for single-step mode
+        single_step = params[:single_step]
+        bumped_major = false
+        bumped_minor = false
+        bumped_patch = false
+
         # Get commits log between last version and head
         splitted = get_commits_from_hash(
           hash: hash,
@@ -107,14 +113,26 @@ def self.is_releasable(params)
           end
 
           if commit[:release] == "major" || commit[:is_breaking_change]
-            next_major += 1
-            next_minor = 0
-            next_patch = 0
+            unless bumped_major
+              next_major += 1
+              next_minor = 0
+              next_patch = 0
+              bumped_major = single_step
+              bumped_minor = single_step
+              bumped_patch = single_step
+            end
           elsif commit[:release] == "minor"
-            next_minor += 1
-            next_patch = 0
+            unless bumped_major
+              next_minor += 1
+              next_patch = 0
+              bumped_minor = single_step
+              bumped_patch = single_step
+            end
           elsif commit[:release] == "patch"
-            next_patch += 1
+            unless bumped_patch
+              next_patch += 1
+              bumped_patch = single_step
+            end
           end
 
           next_version = "#{next_major}.#{next_minor}.#{next_patch}"
@@ -143,6 +161,14 @@ def self.is_releasable(params)
       end
 
       def self.is_codepush_friendly(params)
+        if params[:single_step]
+          # If single-step mode is selected, skip checking last codepush version
+          # as it is likely in the middle of a release.
+          UI.important("Skipping RELEASE_LAST_INCOMPATIBLE_CODEPUSH_VERSION because single_step was set")
+          Actions.lane_context[SharedValues::RELEASE_LAST_INCOMPATIBLE_CODEPUSH_VERSION] = "0.0.0"
+          return false
+        end
+
         git_command = 'git rev-list --max-parents=0 HEAD'
         # Begining of the branch is taken for codepush analysis
         hash_lines = Actions.sh("#{git_command} | wc -l", log: params[:debug]).chomp
@@ -252,6 +278,13 @@ def self.available_options
             type: Array,
             optional: true
           ),
+          FastlaneCore::ConfigItem.new(
+            key: :single_step,
+            description: "Only update the new version by the minimal amount",
+            default_value: false,
+            type: Boolean,
+            optional: true
+          ),
           FastlaneCore::ConfigItem.new(
             key: :debug,
             description: "True if you want to log out a debug info",