feat: Implement exposure (#2173)

* feat: Implement `exposure` (iOS)

* Update Podfile.lock

* Format

* Expose exposure in format

* Set exposure in Camera2

* fix: Fix exposure calculation

* Add exposure docs

package/ios/CameraView.swift

@@ -46,6 +46,7 @@ public final class CameraView: UIView, CameraSessionDelegate {
   @objc var isActive = false
   @objc var torch = "off"
   @objc var zoom: NSNumber = 1.0 // in "factor"
+  @objc var exposure: NSNumber = 1.0
   @objc var enableFpsGraph = false
   @objc var videoStabilizationMode: NSString?
   @objc var resizeMode: NSString = "cover" {
@@ -218,6 +219,9 @@ public final class CameraView: UIView, CameraSessionDelegate {
       // Zoom
       config.zoom = zoom.doubleValue
 
+      // Exposure
+      config.exposure = exposure.floatValue
+
       // isActive
       config.isActive = isActive
     }