ARROW-7849: [Packaging][Python] Remove the remaining py27 crossbow wh…

…eel tasks from the nightlies

Follow-up for #6410

Closes #6415 from kszucs/nightly-crossbow-tasks and squashes the following commits:

6a87514 <Krisztián Szűcs> Remove the remaining py27 crossbow wheel tasks from the nightlies

Authored-by: Krisztián Szűcs <szucs.krisztian@gmail.com>
Signed-off-by: Krisztián Szűcs <szucs.krisztian@gmail.com>

dev/tasks/tasks.yml

@@ -233,14 +233,10 @@ groups:
     - conda-win-vs2015-py36
     - conda-win-vs2015-py37
     - conda-win-vs2015-py38
-    - wheel-manylinux1-cp27m
-    - wheel-manylinux1-cp27mu
     - wheel-manylinux1-cp35m
     - wheel-manylinux1-cp36m
     - wheel-manylinux1-cp37m
     - wheel-manylinux1-cp38
-    - wheel-manylinux2010-cp27m
-    - wheel-manylinux2010-cp27mu
     - wheel-manylinux2010-cp35m
     - wheel-manylinux2010-cp36m
     - wheel-manylinux2010-cp37m
@@ -249,7 +245,6 @@ groups:
     - wheel-manylinux2014-cp36m
     - wheel-manylinux2014-cp37m
     - wheel-manylinux2014-cp38
-    - wheel-osx-cp27m
     - wheel-osx-cp35m
     - wheel-osx-cp36m
     - wheel-osx-cp37m