GH-42232: [C++] Use non-stale c-ares download URL (#42250)

### Rationale for this change

The URL to download the c-ares dependency is stale. Note: we weren't seeing this bonk on most CI because we have the fallback of our own copy of these. But the R script that downloads all of our thirdparty deps always uses the official URL which is the one that had moved.

Resolves #42232 

### What changes are included in this PR?

Use the appropriate URL, muck with `.` -> `_`

### Are these changes tested?

The current CI should pass + the R maximal offline build should pass too

### Are there any user-facing changes?

More reliable retrieval of all thirdparty dependencies
* GitHub Issue: #42232

Authored-by: Jonathan Keane <[email protected]>
Signed-off-by: Sutou Kouhei <[email protected]>

cpp/cmake_modules/ThirdpartyToolchain.cmake

@@ -634,8 +634,10 @@ endif()
 if(DEFINED ENV{ARROW_CARES_URL})
   set(CARES_SOURCE_URL "$ENV{ARROW_CARES_URL}")
 else()
+  string(REPLACE "." "_" ARROW_CARES_BUILD_VERSION_UNDERSCORES
+                 ${ARROW_CARES_BUILD_VERSION})
   set_urls(CARES_SOURCE_URL
-           "https://c-ares.haxx.se/download/c-ares-${ARROW_CARES_BUILD_VERSION}.tar.gz"
+           "https://github.com/c-ares/c-ares/releases/download/cares-${ARROW_CARES_BUILD_VERSION_UNDERSCORES}/c-ares-${ARROW_CARES_BUILD_VERSION}.tar.gz"
            "${THIRDPARTY_MIRROR_URL}/cares-${ARROW_CARES_BUILD_VERSION}.tar.gz")
 endif()
 

cpp/thirdparty/versions.txt

@@ -144,7 +144,7 @@ DEPENDENCIES=(
   "ARROW_BOOST_URL boost-${ARROW_BOOST_BUILD_VERSION}.tar.gz https://apache.jfrog.io/artifactory/arrow/thirdparty/7.0.0/boost_${ARROW_BOOST_BUILD_VERSION//./_}.tar.gz"
   "ARROW_BROTLI_URL brotli-${ARROW_BROTLI_BUILD_VERSION}.tar.gz https://github.com/google/brotli/archive/${ARROW_BROTLI_BUILD_VERSION}.tar.gz"
   "ARROW_BZIP2_URL bzip2-${ARROW_BZIP2_BUILD_VERSION}.tar.gz https://sourceware.org/pub/bzip2/bzip2-${ARROW_BZIP2_BUILD_VERSION}.tar.gz"
-  "ARROW_CARES_URL cares-${ARROW_CARES_BUILD_VERSION}.tar.gz https://c-ares.haxx.se/download/c-ares-${ARROW_CARES_BUILD_VERSION}.tar.gz"
+  "ARROW_CARES_URL cares-${ARROW_CARES_BUILD_VERSION}.tar.gz https://github.com/c-ares/c-ares/releases/download/cares-${ARROW_CARES_BUILD_VERSION//./_}/c-ares-${ARROW_CARES_BUILD_VERSION}.tar.gz"
   "ARROW_CRC32C_URL crc32c-${ARROW_CRC32C_BUILD_VERSION}.tar.gz https://github.com/google/crc32c/archive/refs/tags/${ARROW_CRC32C_BUILD_VERSION}.tar.gz"
   "ARROW_GBENCHMARK_URL gbenchmark-${ARROW_GBENCHMARK_BUILD_VERSION}.tar.gz https://github.com/google/benchmark/archive/${ARROW_GBENCHMARK_BUILD_VERSION}.tar.gz"
   "ARROW_GFLAGS_URL gflags-${ARROW_GFLAGS_BUILD_VERSION}.tar.gz https://github.com/gflags/gflags/archive/${ARROW_GFLAGS_BUILD_VERSION}.tar.gz"