build: add Kristiyan to datepicker code owners (#24592)

(cherry picked from commit b7b96b7)

Author: zarend

.github/CODEOWNERS

@@ -8,7 +8,7 @@
 /src/material/card/**                              @andrewseguin
 /src/material/checkbox/**                          @andrewseguin @devversion
 /src/material/chips/**                             @andrewseguin
-/src/material/datepicker/**                        @mmalerba
+/src/material/datepicker/**                        @mmalerba @crisbeto
 /src/material/dialog/**                            @andrewseguin @crisbeto
 /src/material/divider/**                           @andrewseguin @crisbeto
 /src/material/expansion/**                         @andrewseguin
@@ -162,7 +162,7 @@
 /src/dev-app/column-resize/**                      @kseamon @andrewseguin
 /src/dev-app/connected-overlay/**                  @jelbourn @crisbeto
 /src/dev-app/dataset/**                            @andrewseguin
-/src/dev-app/datepicker/**                         @mmalerba
+/src/dev-app/datepicker/**                         @mmalerba @crisbeto
 /src/dev-app/dev-app/**                            @mmalerba
 /src/dev-app/dialog/**                             @andrewseguin @crisbeto
 /src/dev-app/drag-drop/**                          @crisbeto
@@ -315,7 +315,7 @@
 /tools/public_api_guard/material/chips.d.ts             @andrewseguin
 /tools/public_api_guard/material/chips/testing.d.ts     @andrewseguin
 /tools/public_api_guard/material/core.d.ts              @andrewseguin
-/tools/public_api_guard/material/datepicker.d.ts        @mmalerba
+/tools/public_api_guard/material/datepicker.d.ts        @mmalerba @crisbeto
 /tools/public_api_guard/material/dialog.d.ts            @andrewseguin @crisbeto
 /tools/public_api_guard/material/divider.d.ts           @andrewseguin @crisbeto
 /tools/public_api_guard/material/expansion.d.ts         @andrewseguin