convert watch syntax

[todo]

vue2-migration-helper/src/index.ts

Lines 9 to 14 in 8b0bd34

	// TODO: convert watch syntax
	// TODO: convert methods syntax
	// TODO: convert life-cycle hooks
	// TODO: convert props syntax
	// TODO: update this.$event usage

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This issue was generated by todo based on a TODO comment in 8b0bd34. It's been assigned to @mubaidr because they committed the code.

[mubaidr]

6b26a21