fix: transform uses placeholderPattern: false

[jeremyjh]

We explicitly disable placeholderPatterns to prevent compilation errors
of valid Vue.js templates using Babel 7 transform.

Please check if the PR fulfills these requirements

• The commit message follows our guidelines: CONTRIBUTING.md
• There are no linting errors and code is properly formatted (your run before push yarn lint)
• Tests for the changes have been added (for bug fixes / features)
• [] Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x")

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Other... Please describe:

What is the current behavior? (You can also link to an open issue here)

You can see in the failing test case that a valid Vue.js template is not compiled successfully if it has all caps alone between two-tags. Babel transform assumes this is the start of a placeholder pattern unless it is explicitly told not to do that.

What is the new behavior?

Valid Vue.js templates are always compiled.

Does this PR introduce a breaking change? (check one with "x")

[ ] Yes
[x] No

If this PR contains a breaking change, please describe the impact and migration path for existing applications: ...

Other information:

This issue is referenced here:

babel/babel#8067

[codecov-io]

Codecov Report

Merging #163 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master   #163   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           2      2           
  Lines           6      6           
=====================================
  Hits            6      6

Impacted Files	Coverage Δ
test/fixtures/FooComponent.vue	100% <ø> (ø)	⬆️

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