Merge pull request #206 from PHP-FFMpeg/enhancement/pull-request-template

| Q                  | A
| ------------------ | ---
| Bug fix?           | no
| New feature?       | no
| BC breaks?         | no
| Deprecations?      | no
| Fixed tickets      | -
| Related issues/PRs | -
| License            | MIT

#### What's in this PR?

A meaningful pull request template similar to this pull request description.

#### Why?

Such templates should encourage first-timers to create good pull request descriptions, which helps us reviewing it.

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,36 @@
+| Q                  | A
+| ------------------ | ---
+| Bug fix?           | yes
+| New feature?       | yes
+| BC breaks?         | yes
+| Deprecations?      | yes
+| Fixed tickets      | fixes #issuenum
+| Related issues/PRs | #issuenum
+| License            | MIT
+
+#### What's in this PR?
+
+Explain the contents of the PR.
+
+#### Why?
+
+Which problem does the PR fix?
+
+#### Example Usage
+
+~~~php
+$foo = new Foo();
+
+// Now we can do
+$foo->doSomething();
+
+// Remove this section if not needed
+~~~
+
+#### BC Breaks/Deprecations
+
+Describe BC breaks/deprecations here (Remove this section if not needed).
+
+#### To Do
+
+- [ ] Create tests