Vectorized fill_up weights and run linter on project

[developer0hye]

Thanks for your contribution!

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See https://detectron2.readthedocs.io/notes/contributing.html#pull-requests about how we handle PRs.

Before submitting a PR, please run dev/linter.sh to lint the code.

Actually, I modified 3 lines in dla.py and dla_fpn.py. However, many lines are modified after linter...

Before

CenterNet2/projects/CenterNet2/centernet/modeling/backbone/dla.py

Lines 254 to 263 in f3ffa53

	def fill_up_weights(up):
	w = up.weight.data
	f = math.ceil(w.size(2) / 2)
	c = (2 * f - 1 - f % 2) / (2. * f)
	for i in range(w.size(2)):
	for j in range(w.size(3)):
	w[0, 0, i, j] = \
	(1 - math.fabs(i / f - c)) * (1 - math.fabs(j / f - c))
	for c in range(1, w.size(0)):
	w[c, 0, :, :] = w[0, 0, :, :]

After

CenterNet2/projects/CenterNet2/centernet/modeling/backbone/dla.py

Lines 323 to 329 in f412076

	def fill_up_weights(up):
	w = up.weight.data
	f = math.ceil(w.size(2) / 2)
	c = (2 * f - 1 - f % 2) / (2.0 * f)
	for i in range(w.size(2)):
	for j in range(w.size(3)):
	w[:, 0, i, j] = (1 - math.fabs(i / f - c)) * (1 - math.fabs(j / f - c))