Regen APIs after removal of breaking special case for Rust types

I can just hope it's breaking everywhere and was never working, as
opposed to a special bugfix for just a single API at the time.

gen/monitoring3/src/lib.rs

@@ -637,7 +637,7 @@ pub struct Distribution {
     pub count: Option<String>,
     /// Required in the Stackdriver Monitoring API v3. The values for each bucket specified in bucket_options. The sum of the values in bucketCounts must equal the value in the count field of the Distribution object. The order of the bucket counts follows the numbering schemes described for the three bucket types. The underflow bucket has number 0; the finite buckets, if any, have numbers 1 through N-2; and the overflow bucket has number N-1. The size of bucket_counts must not be greater than N. If the size is less than N, then the remaining buckets are assigned values of zero.
     #[serde(rename="bucketCounts")]
-    pub bucket_counts: Option<Vec<i64>>,
+    pub bucket_counts: Option<Vec<String>>,
     /// The sum of squared deviations from the mean of the values in the population. For values x_i this is:
     /// Sum[i=1..n]((x_i - mean)^2)
     /// Knuth, "The Art of Computer Programming", Vol. 2, page 323, 3rd edition describes Welford's method for accumulating this sum in one pass.If count is zero then this field must be zero.