Update dependency dropdown_search to v3

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
dropdown_search	dependencies	major	^0.5.0 -> ^3.0.0

---

Release Notes

salim-lachdhaf/searchable_dropdown

v3.0.1

• breaking changes:
  • remove 'hint' and 'label' properties, use 'dropdownSearchDecoration' instead
  • remove 'showAsSuffixIcons' property, now always are as suffixIcon
  • replace 'clearButtonSplashRadius' and 'clearButtonBuilder' into one property 'IconButtonProps'
  • replace 'dropdownButtonSplashRadius' and 'dropdownButtonBuilder' into one property 'IconButtonProps'
  • fix issue 380

v2.0.1

• improve performance
• add "popupCustomMultiSelectionWidget" option

v2.0.0

• fix bug 284
• breaking changes
  • add "isSelected" option to FavoriteItemsBuilder
  • change onChange to onChanged in multiSelection mode

v1.0.4

• fix some bugs

v1.0.3

• new feature : change searchBox query programmatically using EditTextController
• fix some bugs

v1.0.0

• new feature : multiSelection mode

• breaking changes :
  - searchBoxDecoration removed: replaced by searchFieldProps
  _ autoFocusSearchBox removed : replaced by searchFieldProps
  _ searchBoxStyle removed : replaced by searchFieldProps
  _ searchBoxController removed : replaced by searchFieldProps

    - showSelectedItem replaced by showSelectedItems
  

v0.6.3

• fix analyser issues

v0.6.2

• prop that passes all props to search field
• fix issues 169
• fix issues 163
• new Feature "dropdown BaseStyle" 178
• new Feature "popup scrollView"
• Ignore pointers in itemBuilder & cursor in web
• Added property to customize DropdownButton Splash Radius
• added property to set up the splash radius for clear button and for dropdown button in dropdown_search
• @​thanks Vasiliy

v0.6.1

• added property to set up the popup safe area
• fixed null safety issues

---

Configuration

📅 Schedule: At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• If you want to rebase/retry this PR, click this checkbox.

---

This PR has been generated by WhiteSource Renovate. View repository job log here.