[libcap] Use official tarballs (#38599)

Fix recurring problem with on-the-fly tarballs:
#38591,
#37948.

ports/libcap/portfile.cmake

@@ -1,7 +1,8 @@
 vcpkg_download_distfile(ARCHIVE
-    URLS "https://git.kernel.org/pub/scm/libs/libcap/libcap.git/snapshot/libcap-${VERSION}.tar.gz"
-    FILENAME "libcap-${VERSION}.tar.gz"
-    SHA512 b243ae403d45af2ff1204931b9e24c3b7f3e0c444f1ff2f3ed524c212b61a7ff1bc3c98df1855b2f0d300ebabf604b95440cdaddd666914ad60575e2e2f29fe8
+    URLS "https://www.kernel.org/pub/linux/libs/security/linux-privs/libcap2/libcap-${VERSION}.tar.xz"
+         "https://www.mirrorservice.org/sites/ftp.kernel.org/pub/linux/libs/security/linux-privs/libcap2/libcap-${VERSION}.tar.xz"
+    FILENAME "libcap-${VERSION}.tar.xz"
+    SHA512 647c307dc451517da9d089495ab959b4a6fbbe41c79f4e1e9bb663569dad630ead0c2e413dfb393319e3ea14dc9848c81b392107fe3382ce1813d278c3394a7f
 )
 
 vcpkg_extract_source_archive(SOURCE_PATH

ports/libcap/vcpkg.json

@@ -1,19 +1,15 @@
 {
   "name": "libcap",
   "version": "2.69",
-  "port-version": 4,
+  "port-version": 5,
   "description": "A library for getting and setting POSIX.1e (formerly POSIX 6) draft 15 capabilities.",
-  "homepage": "https://git.kernel.org/pub/scm/libs/libcap/libcap.git",
+  "homepage": "https://sites.google.com/site/fullycapable/",
   "license": "BSD-3-Clause OR GPL-2.0-only",
   "supports": "linux",
   "dependencies": [
     {
       "name": "libcap",
       "host": true
-    },
-    {
-      "name": "vcpkg-cmake-get-vars",
-      "host": true
     }
   ]
 }

versions/baseline.json

@@ -4222,7 +4222,7 @@
     },
     "libcap": {
       "baseline": "2.69",
-      "port-version": 4
+      "port-version": 5
     },
     "libcbor": {
       "baseline": "0.11.0",

versions/l-/libcap.json

@@ -1,5 +1,10 @@
 {
   "versions": [
+    {
+      "git-tree": "3e58d4ec062b5e83ea7c7f6baf42ebd726af6bc1",
+      "version": "2.69",
+      "port-version": 5
+    },
     {
       "git-tree": "f81a07cf694095f60c759c9a18adc57e94296a5f",
       "version": "2.69",