Update minimum version of webpack to 5.0~

Closes: #1009598

debian/control

@@ -10,7 +10,7 @@ Build-Depends:
  , node-babel-cli
  , rollup
  , jest
- , webpack
+ , webpack (>= 5.0~)
  , node-postcss (>= 8.0~)
  , node-cosmiconfig (>= 7.0~)
 # added as component
@@ -37,7 +37,7 @@ Depends:
  , node-schema-utils (>= 3.0~)
  , node-semver (>= 7.3.4~)
  , node-postcss (>= 7.0~)
- , webpack (>= 4~)
+ , webpack (>= 5.0~)
 Description: PostCSS loader for webpack
  This package is a loader for webpack to process CSS with PostCSS.
  .