Update scikit-image documentation (0.18.1)

Author: simon04

assets/javascripts/templates/pages/about_tmpl.coffee

@@ -755,7 +755,7 @@ credits = [
     'scikit-image',
     '2019 the scikit-image team',
     'BSD',
-    'http://scikit-image.org/docs/dev/license.html'
+    'https://scikit-image.org/docs/dev/license.html'
   ], [
     'scikit-learn',
     '2007-2020 The scikit-learn developers',

lib/docs/scrapers/scikit_image.rb

@@ -3,8 +3,8 @@ class ScikitImage < UrlScraper
     self.name = 'scikit-image'
     self.slug = 'scikit_image'
     self.type = 'sphinx'
-    self.release = '0.17.2'
-    self.base_url = 'https://scikit-image.org/docs/0.17.x/'
+    self.release = '0.18.1'
+    self.base_url = 'https://scikit-image.org/docs/0.18.x/'
     self.links = {
       home: 'https://scikit-image.org/',
       code: 'https://github.com/scikit-image/scikit-image'