Add abseil to the autoroller (KhronosGroup#5680)

The autoroller does not update abseil, and that it stopping us from
updating RE2. This change will update the auto roller, then the next
time it runs, we should be able to update everything.

utils/roll_deps.sh

@@ -29,13 +29,12 @@ function ExitIfIsInterestingError() {
 }
 
 
-dependencies=("external/effcee/"
-              "external/googletest/"
-              "external/re2/"
-              "external/spirv-headers/")
-
-
-branch="origin/main"
+declare -A dependency_to_branch_map
+dependency_to_branch_map["external/abseil_cpp"]="origin/master"
+dependency_to_branch_map["external/effcee/"]="origin/main"
+dependency_to_branch_map["external/googletest/"]="origin/main"
+dependency_to_branch_map["external/re2/"]="origin/main"
+dependency_to_branch_map["external/spirv-headers/"]="origin/main"
 
 # This script assumes it's parent directory is the repo root.
 repo_path=$(dirname "$0")/..
@@ -53,7 +52,8 @@ old_head=$(git rev-parse HEAD)
 
 set +e
 
-for dep in ${dependencies[@]}; do
+for dep in ${!dependency_to_branch_map[@]}; do
+  branch=${dependency_to_branch_map[$dep]}
   echo "Rolling $dep"
   roll-dep --ignore-dirty-tree --roll-to="${branch}" "${dep}"
   ExitIfIsInterestingError $?