Merge pull request #62555 from ixdy/toplevel-OWNERS-filters

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

root OWNERS: escape backslashes in filters

**What this PR does / why we need it**: I didn't properly test my change in #62484, and now the OWNERS file is failing to parse:
```console
$ yq '.' OWNERS
yq: Error running jq: ScannerError: while scanning a double-quoted scalar
  in "OWNERS", line 22, column 3
found unknown escape character '.'
  in "OWNERS", line 22, column 5.
```
(The approval bot is similarly having trouble parsing.)

@cjwagner suspects the backslashes need to be escaped, and that indeed seems to work:
```console
$ yq '.' OWNERS
{
  "filters": {
    ".*": {
      "reviewers": [
        "brendandburns",
        "dchen1107",
        "jbeda",
        "lavalamp",
        "smarterclayton",
        "thockin"
      ],
      "approvers": [
        "bgrant0607",
        "brendandburns",
        "dchen1107",
        "jbeda",
        "monopole",
        "lavalamp",
        "smarterclayton",
        "thockin",
        "wojtek-t"
      ]
    },
    "\\.bzl$": {
      "reviewers": [
        "ixdy"
      ],
      "approvers": [
        "ixdy"
      ]
    },
    "BUILD(\\.bazel)?$": {
      "approvers": [
        "ixdy"
      ]
    }
  }
}
```

**Release note**:

```release-note
NONE
```

/assign @cjwagner 
cc @cblecker @smarterclayton @bgrant0607

OWNERS

@@ -19,11 +19,11 @@ filters:
       - wojtek-t
 
   # Bazel build infrastructure changes often touch files throughout the tree
-  "\.bzl$":
+  "\\.bzl$":
     reviewers:
       - ixdy
     approvers:
       - ixdy
-  "BUILD(\.bazel)?$":
+  "BUILD(\\.bazel)?$":
     approvers:
       - ixdy