update upload-symbols to version 3.6 build 25 (#7323)

This version is code signed with Google's Developer certificate, and has
been "notarized" via Apple's notary service.

```
$ Crashlytics/upload-symbols --version
upload-symbols 3.6 build 25

$ codesign -dv --verbose=4 Crashlytics/upload-symbols

Identifier=com.firebase.crashlytics.upload-symbols
Format=Mach-O thin (x86_64)
CodeDirectory v=20500 size=2131 flags=0x10000(runtime) hashes=60+2 location=embedded
VersionPlatform=1
VersionMin=657920
VersionSDK=720896
Hash type=sha256 size=32
CandidateCDHash sha1=0ec18ed3b6967ad86afa07e3312b886ad7b28337
CandidateCDHashFull sha1=0ec18ed3b6967ad86afa07e3312b886ad7b28337
CandidateCDHash sha256=61c17b9f52e9ad22bf47ea7e57904ceca18cddf7
CandidateCDHashFull sha256=61c17b9f52e9ad22bf47ea7e57904ceca18cddf77e30c813e32b572b066dfd62
Hash choices=sha1,sha256
CMSDigest=317a74ff6c7d3485cb58f4dbec14856cbb53018bdb00336919053070a0f5d017
CMSDigestType=2
Page size=4096
CDHash=61c17b9f52e9ad22bf47ea7e57904ceca18cddf7
Signature size=9042
Authority=Developer ID Application: Google, Inc. (EQHXZ8M8AV)
Authority=Developer ID Certification Authority
Authority=Apple Root CA
Timestamp=Jan 19, 2021 at 10:51:21 AM
Info.plist entries=19
TeamIdentifier=EQHXZ8M8AV
Runtime Version=11.0.0
Sealed Resources=none
Internal requirements count=1 size=200
```

Author: adamvduke

Crashlytics/CHANGELOG.md

@@ -1,3 +1,6 @@
+# Unreleased
+- [changed] Updated upload-symbols to a version that is notarized to avoid macOS security alerts (#7323).
+
 # v7.4.0
 - [changed] Removed obsolete crash reporting mechanism from the SDK (#7076).